How to Clean Car Battery Terminals

When you turn the ignition key to start your car and absolutely nothing happens, you’re first thought is always of a dead battery. Something has happened to drain it such as leaving a light on. But if you pop the hood you might find that the culprit is a greasy, dirty, or corroded battery terminal.

Battery Terminal Corrosion

The problem arises more often if you don’t drive your car regularly. When the engine is not running and the battery is sitting, the terminals oxidize at a faster rate. This means you need to check the battery terminals more often for corrosion. Corrosion appears as a white, ashy deposit around one or both battery posts. Sometimes there is also a bit of color mixed in. These deposits are the result of one of several possible chemical exchanges involving vapors and the battery post.

How to Clean Car Battery Terminals


  • A combination tool – battery post brush and battery clamp brush, obtainable at any auto parts store, or online. These generally come in two designs, one employing wire brush elements and the other using two cutting blades and a reamer. Though old pros prefer the latter, either will work and either is suitable if you’re not cleaning battery posts on a daily basis.
  • Locking pliers (vice grips).
  • Toothbrush.
  • Baking soda.
  • Water.
  • Clean, lint-free cloth.
  • Wrench.
  • Grease or petroleum jelly.


  1. Remove the battery cables from the battery terminals by loosening the nut on each cable clamp. Once they are loose, always remove the cable clamp from the negative terminal first. It’s marked with a minus (-) sign; the positive terminal has a plus (+) sign. Reverse the procedure, positive first, negative second, when replacing the cables. The cable may not come off easily. You will have to wiggle it and lift it upward until the clamp comes off the terminal post. Sometimes, especially if there is a lot of corrosion, you may need the assistance of pair of locking pliers. Be careful not to short any tools you use against the car when they’re in contact with the battery.
  2. Examine the battery cables and clamps for excess wear or corrosion. Should damage appear extensive, replace the cables and clamps to avoid future problems.
  3. Check the battery case for cracks and the terminals for damage. If you find either, replace the battery.
  4. Secure the loose cables so that they don’t accidentally flop back onto the terminals.
  5. Pour some baking soda directly onto the posts.
  6. Dip a toothbrush in water and use it to scrub the baking soda into the terminal posts and cable clamps. Skin and eye protection is recommended.
  7. If the toothbrush isn’t doing the job, Use a battery terminal cleaner brush on it. Also shine up the insides of the cable clamps by using the clamp cleaner that usually comes attached to the terminal brush or use a plain, soap-free steel wool pad.
  8. Dry everything off with a clean, disposable, lint-free rag.
  9. Smear grease or petroleum jelly on the posts to slow down the formation of corrosive deposits. Cover all exposed metal surfaces on the battery posts, battery cables, and clamps.
  10. Replace the positive clamp first and then replace the negative clamp. Tighten them down with the proper sized wrench.
  11. Replace the rubber boot or plastic shield that covers the positive terminal. If you don’t have one, go and buy some from your local auto parts store.

Penny on Battery Post?

We have heard of a trick of using pennies placed on top of the battery, one held in place with a drop of oil near each post. The copper supposedly draws corrosion off the battery terminals. We don’t know whether this works or not – if you know, please let your fellow readers know using the comments at the bottom of this page.


  1. Sharon says:

    My mechanic told me this one. Take a can of Coke and pour a small amount on the corroded terminal. It will literally dissolve the corrosion. Finish by making sure the connection to the terminal is tight.

  2. Don says:

    Wear eye protection and rubber gloves. Remove the battery negative terminal clamp and then the positive terminal clamp. Apply a mixture of one ounce of baking soda and four ounces of water to the terminals and clamps. Let it stand for 10 minutes. Rinse it off and then brush the surfaces with a wire brush (available at any auto parts store). Use a small knife to clean those tight areas. Install battery post corrosion prevention disks (also available at all auto parts stores) or apply a small amount of silicone grease to all surfaces of the terminal and clamp. Reinstall the positive battery clamp first and then the negative. To avoid unexpected breakdowns, follow this procedure at least once every two years. Now you are good for another two years.

  3. Adam says:

    If your stuck somewhere and limited tools or cleaning products are available. Try plain old coffee; it works quite well. Either dip and soak the cables in a cup of joe, or pour it directly on the terminals. A little water to wash the mess away, and your ready to roll.

  4. Kathleen says:

    If your car battery or anything with rust on the car is dirty and hard to clean, just dump some coke (soda) on to it. It will bring it right off. True stuff; cops use it to get blood off sidewalks. Pepsi does not do it – has to be Coke.

  5. Thomas says:

    Regarding the ‘penny on the battery’ idea, copper does not corrode as easily as the lead does. This makes the idea of a penny kind of silly. Not to mention the fact that defacing US Currency is against the law. A better way to prevent the corrosion is much simpler than using a petroleum-based substance; enamel paint. Not a spray paint, but modelers’ enamel paint. I prefer black and red, myself, and I clean the terminals and posts, however on most modern cars, the posts are on the side and do not protrude from the battery. This brings up a new dilemma, that of protecting the side post type batteries and terminals from corrosion. For this, there is more than one solution. The first involves the terminal ends that are supplied with the vehicle that cover the side posts of the batteries. I simply put a rubber washer with a hole in the center for the battery bolt to pass through, not thick rubber just a thin piece of rubber that will extend past the stock terminal ends. The purpose being to keep any and all moisture laden air from the lead posts. The other option is for those with the replacement terminal leads that are usually zinc-coated steel or in some cases a lead mixture. For these I use the enamel to paint the terminals prior to assembly and then touch up when on the battery. It works very well. As for the cleaning, I find a small but stiff wire brush that looks like a toothbrush to be very useful, and I use only the steel, as the brass ones will not clean well. Chemical cleaners leave a residue that is not conducive for the adherence of the enamel. Well, that’s all I have; be safe and well.

  6. George says:

    The really easy way to do it is to use a kettle of boiling water and slowly pour it over the terminals. Do it one at a time and make sure you don’t get water shorting the two posts.

    Yes it’s lazy, yes it’s easy and yes it works. Use Vaseline to cover the terminals when you have finished. Job done!

  7. Mike says:

    I use Baking Soda mixed with water in a plastic cup, a heaping tablespoon of soda in 6-8oz of water. Important, remove negative cable first and then the positive cable & dip them in the baking soda water solution, including a couple of inches of the cable (the cable wire gets corroded too) until the bubbling stops.

    Then, with fresh baking soda mixed with water, wash the whole battery with a brush, (the mixture won’t hurt the battery) and let it run down to the metal battery holder that’s supporting the battery. I had to change one once because it was so corroded.

    I’ve used regular grease to coat the terminals & posts, but found out that The Blue Marine Wheel Bearing Grease (available at Pep Boys, etc., is very water resistant & durable); works much better.

    If you do nothing at all, at least take a napkin & clean a finger-sized straight line between the two posts to break the electric connection between the two posts, The dirt will connect the negative & positive posts together and cause a high resistance short & slowly drain your battery.
    Also, a slow 3-5 amp charger put on your battery every 3-6 months or so for 12-24 hours will make your battery last longer and; if you’re a Do-It-Yourselfer & don’t want to be stuck with a dead battery, (these new starters that take less amps to turn over don’t give you the warning like the old ones & a car that started OK yesterday can be dead in the water today), after a few years, buy a new battery on sale & stick it in the garage for that time that you don’t want to be late for work or when the family’s in the car ready for mom’s thanksgiving dinner & you have to unload the car, call your brother to take you to one of those 24/7 auto parts places that will charge you top dollar for a battery that you wouldn’t normally buy…!!

  8. James says:

    Water in a spray bottle with jet adjustable spray. You may have one already. Simple as that. Does the job.

  9. Greg says:

    Since this is basically what I do for a living, I do have my take on this.

    Always wear proper protective gear! I wear safety glasses and use nitrile gloves any time I work on a battery. Keep in mind that the acid will eat through clothes as well. Avoid all sparks and open flames when dealing with batteries as they produce hydrogen sulfide gas when they go bad and it is very explosive. You do NOT want a battery to explode on you.

    If the terminal has a build up of acid on it, well the terminal and use a paper towel to remove as much of the acid as possible first. Pour baking soda on it, and wet it down just enough for it to start bubbling. When it stops, add a little more water. Continue until it quits reacting. (Note: Coke will clean the metal as it contains phosphoric acid, but you want something other than an acid to counter an acid.

    Loosen the cables. IF they are really tight, use a little WD-40. Remove the terminals, negative then positive, and use a battery terminal cleaner to clean the terminal and connector. IF it is a side terminal battery, you can use any wire brush to clean the outside. I prefer not to use the bladed cleaners as they are not that easy to use and if you remove too much off the terminal, the connector will not fit tight. Use WD-40 to clean any exterior dirt and grease off the connectors. Replace the cables in reverse order, tighten them and you should be good to go. I do not advocate the use of greases on the terminals as I have had several cases of cars not starting where all I had to do was clean the ‘anti-corrosive’ grease off them and they started.

    Something to keep in mind, try to use a battery minder when doing this. Some vehicles, when they lose the power, will cause you problems. Alarms will go off thinking they are being tampered with. Some anti-theft radios will require you to put in a code before they are usable again. On some cars, the computer temporarily forgets who it is and you have to run the car basically with your foot on the gas for around 15 minutes before it resets itself. Some of the newer cars are even worse. There is a new high-end car (which will remain nameless) that if the computer is lost, it takes almost three days to reset. Good luck.

  10. Mike says:

    Corroded terminals?

    Grab a coke, diet or regular. Drink half.

    Pour the rest on the terminals slowly.

    Like peroxide on a cut, it fizzes all up and ‘voila’ – corrosion all cleaned up.

    Rinse with water. Tell your friends.

  11. Richard says:

    Go to the car parts store and buy a set of the little green and red felt washers. Lube them up with the glop that comes with them and install them around the posts under each clamp. Voila. No more corrosion, ever and no more need to clean.

  12. Craig says:

    Several of the posts mentioned disconnecting the negative cable before the positive. THIS IS EXTREMELY IMPORTANT. The reason for this is that if you try removing the positive cable first and your wrench comes in contact with the car and positive post at the same time, you will have a direct short to ground that can cause burns, sparks and generally mess up your day.

  13. Andrew says:

    After cleaning the battery terminals mix a quantity of soap powder into cream with hot water, pour the paste over the terminals and as long as it is not washed off, it will stop the corrosion.

    Never had problems for 12 months.

  14. Jackie says:

    Wet cell batteries will always cause acid and its fumes to cause corrosion to the terminals, cables, metal tie down bar, and “J” bolts. This is an accepted fact with wet cell batteries. I have owned an OPTIMA battery for two years now without encountering the problems related to the wet cell. When the time come to replace the wet cells on our two other vehicles I will be shopping for one similar to the OPTIMA. The extra cost is well worth not going through the trouble of maintaining a wet cell!

  15. Mary says:


    Pennies are no longer made of copper. The US mint began using other metals for pennies sometime back in the sixties or earlier. If you have a “wheat penny,” it is more likely to be made of copper. Wheat pennies have two stalks of wheat on the back of the penny instead of the Lincoln memorial.

  16. James says:

    Be careful to avoid any washing fluid damaging the driveway or garage floor. The fluid may corrode the surface as it did when I cleaned the terminals.

  17. Calamari says:

    I put a grocery bag and then some newspaper underneath my car when I cleaned my posts. I do recommend safety goggles and gloves (what type, dunno) as my hands are itchy now from minimal contamination. I used a baking soda/water product and a toothbrush for most of the work. I couldn’t get the terminal cables off, but after reading about the order of negative and positive, I am glad. Also, WD-40 sounds good for help. Sounds like the mechanic knows of which he speaks, so I won’t use any grease on the posts. Thanks for all the input!

  18. James says:

    Just a reminder to those in the know: the use of the wire type cleaning tools should be avoided as it hastens the battery life due to metal getting into the soft lead terminals. Automotive stores sell these cheap or give them away as they know you will soon be back to buy a battery once these are used.
    Stick with the baking soda and toothbrush (plastic bristles) for cleaning.

  19. Steve says:

    There are many good tips here and also a few it would be best avoiding.
    I will provide some explanation to help with understanding the “why’s?” so you can make informed decisions about these yourself.

    1) If it is an option, it is recommended to use baking soda and hot water to clean the corrosive buildup on your battery posts rather than plain water, Coke, or coffee:

    Why? Just using plain hot water, Coke, or coffee to clean the acidic buildup on the battery posts will create a highly corrosive acidic solution that will run all over various parts in your engine compartment, driveway, and garage floor. This will cause unnecessary corrosion on anything it touches. Including; Etching paint speeding corrosion of metal parts, softening rubber possibly causing failures, removing the finished surface of concrete or asphalt, not to mention the obvious skin, eye, and clothing concerns. The baking soda & water is a basic (low pH) solution, which will actually neutralize the acidic (high pH) solution preventing this corrosion. The hot water simply acts as a catalyst to speed the cleaning and the reaction. It is still advisable to rinse the area with clean water once you are complete.

    2) It is best to use non-abrasive brushes to clean and service your battery posts and clamps.
    Why? Wire brushes and reamers will remove too much of the soft lead material material used to make battery posts and most post clamps. Once too much material has been removed, the clamp will not tighten properly on the battery post causing a loose connection and compounding your problems. If these parts cannot be cleaned successfully using non abrasive methods use caution when employing any abrasives being aware that the lead material can be removed or badly damaged easily with cutting tools or abrasives.

    3) Remove the negative battery terminal first then remove the positive battery terminal.

    Why? For safety reasons it is advised to remove cable leads in this manner. A charging battery creates a dangerously explosive hydrogen gas which can be ignited by an electrical spark (arc), which may cause the battery to explode, spraying the hydrochloric acid contents causing severe flash burns and acid burns to skin and eyes. Since it is far less likely to get arcing from removing a negative terminal than a positive terminal, this is the preferred method. Once the negative terminal is removed and away the from the battery, the circuit is broken and the positive will not arc.

    Note: This is remote, but it does happen, it is not meant to scare you from performing this simply to inform you to insure you take the required precautions which will allow you to proceed worry free.

    Happy Cleaning!

  20. Don says:

    The baking soda method is the safest. The penny thing is a waste of time. I did like the comment about ‘Defacing US Currency is against the law.’ I’m assuming that was not a serious comment. I sort of doubt the Secret Service will throw you in jail for attempting to use a penny to keep your battery from gunking up. Coke works, but remember, if the stuff burns off corrosion, it can burn off other stuff.

  21. Suzy says:

    Here’s a weird one for you: My terminals had no visible deposits around them, yet my car would start strongly sometimes and then not start until the second or third try other times. Is it possible to have no obvious deposits, yet have enough to affect starting? I was in a hurry to get to the post office before they closed, so I quickly mixed up a couple tablespoons of baking soda into some hot water, about 3/4 of a cup I reckon, poured it over each of the terminals (they were very tight, btw) and voila~ the car started immediately. No problem since either. Hope this bit of trivia helps someone as much as the above info helped me. Cheers! :-)

  22. Sue says:

    No tip, but a question. White ash was all over the battery, but the terminals were fine! Brushed the ash off, but don’t know what caused it. Any thoughts? As I said, the terminals were clean.

  23. Barrett says:

    My car wouldn’t start when I got back from having lunch and I just so happened to still have a Coke (diet) with me – worked like a charm, I was able to start her up and drive home (where I used the baking soda + hot water method) and she’s been running like a champ since. Thanks for the tips, everyone!

  24. Eashwaran says:

    Baking soda did wonders! The terminals were really tight and I’d given up hope, when I read this page and the advice in here. Great website and great advice. Thanks! :-)

  25. Dave says:

    Pennies are made of 99.4% zinc these days, which is an ideal metal to use as a sacrificial anode, drawing corrosion away from other metals. They are used on ships, bridges and other structures susceptible to corrosion, so I would imagine this would probably actually work.

  26. Michael says:

    To set the facts straight about the penny:

    Pennies prior to 1982 are bronze compositions: 95% copper and 5% zinc/tin (tin was only used until ’62). This holds true since before 1900 with the exception of 1943 when steel was used instead of copper.

    Pure copper hasn’t been used for over 150 years.

    Since 1982 pennies are copper plated zinc with 97.5% (not 99.4) zinc. They are still plated with copper, so if you use one, don’t use a brand new one as it will take longer to become effectively sacrificial.

    Therefore, if you are to use a penny, make sure it is dated after 1982 and isn’t too glossy or “copper” colored. Don’t use any other coins such as nickels, dimes, or quarters as they are all still copper alloys.

  27. Kooch says:

    Nice discussions and good tips. Just did mine today after noticing slow cranking in temps below 5 deg. F last several days. Of course, better planning in order: a nice warm fall day! One poster gave a reasonable explanation of the chemistry involved here, i.e. the corrosion is an acidic compound which is neutralized by the basic baking soda (some people drink a bit of the stuff mixed with water to relieve heartburn). That poster did, however, get his acid-base pH numbers backward: the lower the pH, the more acidic, 7 is essentially neutral (e.g. water), and above that is in the “basic” (not basic in the sense we often use it) range. Our stomach secretes HCL (aka hydrochloric acid), and a form of this is known as muriatic acid, often used to clean brick when repainting. On the other side, with respect to strength and potential tissue damage, are the strong bases like sodium hydroxide or (NaOH) or common household bleach, which is sodium hypochlorite. The bases are also referred to as alkalies (al-kuh-lies). So everyone recommending eye protection is exactly right, and another important thing: especially on a day like today when its cold and stuff is running down your face, do not rub your face with your hands while working with corrosives! (I didn’t.) After the procedure (I coated the already snugged down cable clamps and posts with Vaseline because I did wonder if the grease would interfere somewhat with conduction), I did believe I got a cleaner sounding start, but tomorrow morning will be the real test. Thanks for everyone’s input.

  28. Howdy Doody says:

    I used baking soda and quick start on the carburetor and bought a can of terminal lubricant so no further corrosion.

    Also, you can put a cardboard box over the battery in cold country and it will start easier. You have to remove it prior to starting, but worth it for me at least. Now to find Clarabelle.

  29. Ed says:

    The fact used to be that the world was flat. Once the terminal clamps and posts are clean and corrosion free, simply put a light coat of good old Vaseline brand petroleum jelly on the inside of the terminal clamp holes, and on the posts. You will never see corrosion on there again. I have been doing this for 35 years. Do not put too much on them because naturally, too heavy of a coat, will attract grease and dirt, but even if you’re over doing it, check it in a week or so, and just wipe off your excess.

    I hope this helps someone,

  30. KC says:

    Think about what Coke (soda in general) does to your teeth!!!

  31. Bob says:

    Great tips, but remember that baking soda cuts the acid ON the cables AS WELL AS IN the battery also. Use care not to neutralize your battery by accident. Keep the soda away from the fill holes on the cells.

  32. Erik says:

    “No tip, but a question. White ash all over the battery, but the terminals were fine! Brushed the ash off, but don’t know what caused it. Any thoughts? As I said, the terminals were clean.”

    There was enough dirt and moisture for current to leak across the top of the battery. Let this go long enough and sooner or later it will kill your battery. The easiest prevention is to just wipe off the top of your battery whenever you change your oil (or after you get home from having your oil changed).

    I have to second the recommendation on the Optima batteries. I have fifteen years of experience using these batteries and there’s nothing that compares. Very reliable and low-maintenance.

  33. Darlene says:

    Here is something I learned from my dad (a mechanic) and confirmed when I took automotive technician classes.

    Whenever the weather is below 30, turn on your car’s headlights for about 2-3 minutes, then turn them off, BEFORE you try starting it. What happens is this: when a battery is cold, it has less available energy, kinda like us when we get cold. By turning on the headlights, we cause the electrons inside the battery to start moving around and rubbing against each other. This causes friction and friction generates heat, thus raising the available energy. I don’t remember the exact ratio, but for every degree below 60 degrees F., the battery “lost” a percentage of its’ available energy.
    And of course, if the car’s engine oil is cold, it takes a lot more to turn the engine over. Electric dipstick heaters work fairly well, just be sure to remove it before starting the car. Another way of keeping the engine warmer is to place a layer or two of heavy duty aluminum foil over the main engine components topped by cardboard while the engine is still hot from driving. Again, remove before starting. Throwing a tarp or heavy blanket over the car hood helps a lot, too.

  34. Anmi says:

    If the penny is made of copper (new ones are mostly aluminum) it WILL have an effect. The copper works as a sacrificial metal because it has a different electronegativity. They use this same trick to protect hot water heaters and ship hulls. Another poster said that the lead corrodes more than the copper; quite the opposite is true. For the penny to work, it must be in electrical contact with the thing it is protecting. When the penny is all corroded, the bolts (iron) will start to corrode, but not until the copper is consumed. An even better material to use would be magnesium. (That’s what they use in water heaters and on ships.) Look up “cathodic protection” for more info on this phenomenon.
    Corrosion happens when oxygen in the air combines with the metal (usually the iron bolts or copper wires) and this is helped by the presence of a voltage and maybe even some acid (source of H+). ANY EFFECTIVE TREATMENT INVOLVES KEEPING AIR FROM TOUCHING THE METAL. Paint is a stupid idea; silicon lube or WD-40 work, but aren’t thick and wash away easily. Use a LOT of grease and you won’t have problems. If you have corrosion, the baking soda ideas will all work. I recommend an overnight soaking of the entire connection (if they’re molded on) including the first 1/2″ of wire. Use plenty of baking soda and stir it up every once in a while. Never rush out to buy the bolt-on connectors – they’re never as good as the molded ones because, you guessed it, it’s easier for air (the enemy) to get in there.
    If you have already cut off the connector and don’t have any options left, clean the copper wires. Get any grease and then tin them (all together) in solder. Don’t use plumber’s solder because it has ACID in its core. USE ROSIN core solder and, since there will be a lot of corrosion (by electronics standards), you might need extra rosin – available at electronics stores for about $6. The solder won’t stick until the copper is both clean and hot. You’ll need a powerful soldering tool because a thick copper wire can dissipate a lot of the heat and carry it away. A propane torch can also be used if you know how to handle it.

  35. Xavier says:

    Sorry Ammi, apparently some of the earlier posters have it right. According to “,” the current (June 12,2009) US Mint specifications call for the blanks used to mint the penny to contain: .975% zinc, and .025% copper. So, as of yet at least, our pennies contain no aluminum.

  36. John says:

    ‘Defacing US Currency is against the law.’

    Whoever wrote that must be a robot.

  37. Yma says:

    Coke worked well for my car terminals!

  38. Workin' at the says:

    I just today cleaned mine off at the car wash. I just pop the hood and give a quick pass over the engine compartment. No “degreaser” or “engine cleaner,” just the usual soap setting. Same quickie during the rinse. I used an old towel to dry and wipe things within. It killed the towel, but things looks quite nice under the hood. The battery terminals look great.
    Actually, I came here to explore whether I should put Vaseline on the fresh terminal connections. After reading the comments so far, I’m inclined to agree with the enamel paint on clean metal approach. Granted, I’m neither a metallurgist, mechanic, chemist, nor numismatist.

  39. Jenny says:

    The guy at the oil change store told me to use Coke, which corroded the battery cables – big mistake!

  40. Mike says:

    I always kept my terminals clean with the felt washers and baking soda/vinegar mix. The other day, my hot rod wouldn’t start even with my ‘clean’ terminals. I went to my mechanic and he gave me a device which goes over the terminal and scrapes a thin layer of metal off and another to fit inside the cable metal to do the same. It makes them shiny and clean. He does it with all NEW car batteries, as he said there is a covering on them that in time will not allow the juice to flow. I was amazed and would never have believed it, as I had the terminals as tight as can be.

  41. Me says:

    Pennies were 100% copper up until the end of 1984.

    Now, they are 98% zinc with a 2% copper coating.

  42. Cindy says:

    My car is sitting at a convenience store; I think it won’t crank due to corroded terminals. Do I have to remove the cables before I use the baking soda and water paste or can I just apply a bit on each terminal with the cables in place? If I can get it cranked, I will take it to the shop to be cleaned properly. Thanks!!

  43. Jeremy says:

    Thanks for the tips; now I can get my dune buggy going.

  44. Rob says:

    The penny trick WILL work! The only stipulation is that you use a penny dated 1982 – present. In 1982, the newly minted penny was made from 95% Zinc instead of its previous version which was 95% copper, and we know there are few metals more noble than copper that will cause it to corrode. Zinc, on the other hand, is far less noble than most every metal (other than magnesium). Therefore, when the electrochemical properties of the materials are looking for a material to take from it, will take from the zinc inside the penny. As a mechanical engineer, I have used sacrificial anodes such as blocks of zinc so that corrosion attacks the zinc before carbon steel and other materials.

    But since this discussion forum was for “how to CLEAN your battery terminal,” this will merely protect your battery terminals and connectors. Remember conservation of mass from science class? If you take from one metal, you will add to another so the battery may still build up the powdery substance, but at least this will come from the penny and not from the battery or the terminal connectors.

  45. Andy says:

    I was in the automotive preventative maintenance industry for 14 (1993-2007) years. I can’t tell you HOW many battery terminals I cleaned over the years. I CAN tell you that I clean A LOT of terminals… with pennies on them. They were corroded just as bad as terminals without pennies.

    I used (and still do) a product made specifically to clean corrosion from terminals. It’s made by Permatex. It’s very inexpensive and can be bought at most parts stores. Follow the directions on the can… it’s ridiculously simple.

  46. Prescott says:

    It’s only illegal to deface currency if you intend to use it fraudulently as US currency again or sell it, like a collectors edition, especially coins.

    You can mutilate the crud out of a penny if you want. Just don’t use it as currency again.

    The US Mint talks about it here:

    And the statute:

    Title 18 United States Code, Section 331

    “Whoever fraudulently alters, defaces, mutilates, impairs, diminishes,
    falsifies, scales, or lightens any of the coins coined at the mints of
    the United States, or any foreign coins which are by law made current
    or are in actual use or circulation as money within the United States;

    Whoever fraudulently possesses, passes, utters, publishes, or sells,
    or attempts to pass, utter, publish, or sell, or brings into the
    United States, any such coin, knowing the same to be altered, defaced,
    mutilated, impaired, diminished, falsified, scaled, or lightened –

    Shall be fined under this title or imprisoned not more than five
    years, or both.”

  47. Eric says:

    If you find yourself without Coke or baking soda handy, you can use your pocket knife to carefully “skin” the battery posts until they’re shiny. I had to do it to mine today, and it worked great. Just be careful not to take too much metal off.

  48. Chris says:

    I just bought a car that had been sitting outside for a few years. Battery was completely dead of course and removing the connectors was a problem as the bolts and nuts were very rusted/corroded. I had to hacksaw the bolts to get them off. The connectors are fine and I’d rather not put on new ones, but where can I find replacement bolts of the right type?

  49. Wes says:

    RE: Thomas October 2, 2007 at 12:27 am

    It is not illegal to deface US currency. I can take my coins and melt them down and/or burn my bills till they are ash.

    What IS illegal is defacing currency and THEN attempting to use it as currency. Haven’t you ever read the “penny souvenir” machines? They explain right on the machine why what they do is legal.

  50. Melissa says:

    Putting a penny on the center of your battery does work. I have had mine on for years and the penny is corroded, but not my terminals. The trick to that is to get a penny that was before the world wars because there is more copper in it than there is today. Nowadays it is mixed with another metal. Mine is held on with a rolled piece of electrical tape. :)

  51. Dan says:

    It’s the same principle as a sacrificial anode in your swamp cooler. The corrosion attacks the “weaker” metal. I don’t know about the pre-war copper stuff… Pennies are still 95% copper.

  52. Nydank says:

    Pre-1982 pennies are all 95% copper (with the exception of the 1943 steel cent). Post 1982 pennies are actually copper plated zinc. Not sure if that would make a difference in this case or not though.

  53. Ralph says:

    When I was a kid, there was something my dad did every time he checked the oil level in the car. He would pull the dipstick and put a couple of drops of the motor oil on each post. He never had any corrosion on the battery terminals. I never had a chance to try it ’cause I had a Chevy with side-mount cables, which my dad hated because he was a Ford guy.

  54. Matt says:

    I was told to put any grease on the terminal to ‘seal’ it from the elements. I would assume oil from the dip stick would give the same short term protection, thus the need to re-apply every time you check the oil. I would not suggest greasing the cable before attaching; that would most likely cause a poor contact.

  55. Mark says:

    I heard that you should indeed put grease on the bare battery post before reattaching the cables. The grease is actually supposed to help conduct electricity. Is this true?

  56. Katie says:

    I just bought a new battery, and the salesman told me that you should grease the terminals and posts to prevent corrosion. He said to put it on after everything is attached, though.
    He also suggested felt washers that you put over the posts before you connect the terminals.

    Together, I hope that my new battery lasts longer than my last one.

  57. Mark says:

    My local NAPA guy agrees with Katie…

    Do NOT put grease between the battery post and the terminal lug at the end of the battery cable before connecting the terminal to the post. Instead, simply clean the post and inside of the terminal (NAPA actually sells a $5 tool that does both jobs) to get both surfaces down to bare metal, and THEN after connecting the cable, apply grease over the post and connected terminal to reduce corrosion.

  58. Huertkc says:

    Your best bet is to pick up a new set of terminals, whether or not you damage them. If its already rusted, then you might have issues tightening the wing nut back (if you don’t damage it), which could lead to a bad connection. They’re cheap, only a couple bucks for a pack of two.

  59. Huertkc says:

    I forgot to mention that as long as there is a little slack in your battery cables, installation will be a breeze. At most you’ll need a razor blade, a pair of dikes, a screwdriver, and a ratchet set.

  60. Scotty says:

    As a chemistry teacher, a research biochemist, and a former nuclear engineer who was directly responsible for the lead-acid storage battery on a submarine (as well as for running the nuclear reactor and associated electrical systems on said submarine), I am appalled at the disinformation running rampant here…

    Sulfuric acid is what is used in a lead-acid storage battery, not hydrochloric acid. The sponge lead and lead (IV) sulfate plates will not work with hydrochloric acid.

    Electrons are continually moving at the speed of light, according to modern quantum theory. Even if we could get them to absolute zero (not possible on earth, even in the winter…), the electrons might still be moving. They certainly do not ‘rub together’ to generate heat. Good Lord, if electrons caused heat by ‘rubbing together’ or ‘moving around quickly’, we’d be burning up all the time. FYI, beginning chemistry involves little more than finding out how to ‘push around electrons’ amongst and between atoms, while realizing that because of their negative potential, they do not come in contact with one another. Simple quantum mechanics, and even outdated Bohr mechanics would dispute that idea a great deal.

    Copper will not act as a sacrificial anode in any system that has lead present, especially not battery terminals. The lead is more reactive than the copper. Period. Go look up ‘metal reactivity’ or ‘activity series’. Perhaps trace amounts of other metals (zinc especially) in pre-1982 pennies or large amounts in post-1982 pennies is responsible for the anecdotal claims made here. However, I find no empirical data, peer-reviewed studies, or hard science supporting the claims made herein.

    In the navy, we used zinc blocks as sacrificial anodes. I’m not sure why anyone would use magnesium. It tends to be more pricey than zinc, is far more reactive in a variety of situations, and is also highly flammable under the right conditions. In fact, I can burn magnesium inside a chunk of dry ice (pure carbon dioxide) and do so every year to the delight of my students. While magnesium could certainly be used, I would question its prevalence.

    Further, copper has a lower electronegativity than lead (1.95 vs. 2.33) on the ‘Pauling Scale’, which is not the final determiner of electronegativity, but would work for most. Lead has a far lower (by 30 KJ/mole) ionization energy as well, so electrons are not going to be leaving copper as readily as lead, which will result in more reactivity in general at the lead terminal.

    This forum is clear evidence of why science education is important, and a key indicator of why science education in America needs reform. When high school kids around the world look at these posts and laugh, something is wrong. (I used this forum as an example to my kids of why not to believe everything adults say…get evidence for themselves).

    Here’s hoping you all clear up your own personal misconceptions, tightly though you may hold them.

  61. Chris says:

    While I don’t doubt the veracity of the scientific information in your post, there’s no need to refer to other posters as generally uneducated and it does not reflect poorly on the general level of science education in this country. It’s easy enough for someone who works in this field on a daily basis to spout off smugly at how much they know, but coming from someone with a fairly good science education, I can tell you that the information in your post is hardly something most people should have to know. The fact is, I probably did learn much of it during my science classes, but because I almost never use it, it has slowly been replaced with more useful information.

    I’m sure I could spin your head with how much I know about computers and software engineering. Does that mean your education was inadequate? No, it does not. In the same vein, the fact that people don’t know anything about the “Pauling Scale” is not indicative of their lack of education.

    I’m happy you were able to post some helpful information about the subject at hand. However, there’s no need to be smug about it.

  62. Jordan says:

    Chris is right.

  63. Mona says:

    While I did take chemistry in high school, it’s been a long time since I was IN high school. I also don’t have a job as a chemist or as a chemistry teacher, I’m just lucky to remember what an electron is.

    So could someone please restate, in everyday usable language, what is the best way to clean off corrosion on a car battery terminal and also, what is the best way to prevent it from happening once you clean it? Thanks.

  64. Huertkc says:

    Coca Cola works well. I didn’t have any in the house when my battery died a couple weeks ago, and my terminals were EXTREMELY corroded. Believe it or not, I used toothpaste and an old toothbrush with some hot water (don’t know whether or not the temperature matters lol) and it worked fine. Rinse off with some fresh water a couple times and I was golden. Now, to seal it, get a fresh pair of felt terminal protectors and put them on. Then re-install the terminals. For added protection, they sell a spray that seals the terminals, kinda like the effect of coating them with di-electric grease. But remember, the sealing should be down AFTER re-installation.

  65. Melissa says:

    LOL… They sell this awesome cleaner that is color activated when it is sprayed on acid. It’s made by CRC; in a red can. It sprays on yellow and anywhere there is acid, it turns red. I like this stuff because you can see where the battery is breathing. I put it on the whole battery because you cannot see the acid and you DO NOT want it to touch your skin or get on your clothes. Use a wire brush to remove the corrosion or any brush that will do the trick (don’t touch the wire brush to the neg. and pos. terminals … you will start a fire on the brush or shoot up sparks lol). If it’s really bad, let them soak in the chemical until you feel that you can remove it all. Put water on it to remove the chemical and acid corrosion and paper towel it dry or spray air on it (if you have an air line and compressor). As far as protecting them… felt is OK, not going to stop anything and if you don’t tighten them enough, you will have a loose terminal and could have problems in the future. I would buy the protectant spray … my favorite CRC … Or put di-electric grease or Vaseline on it. But you really need to make sure it’s very dry or you’re going to lock moister in. Coke or baking soda with water works just as good. I personally like to see the acid lol and the colors change ha-ha. Just remember to check your water in your battery because when you do have corrosion, it tends to lower your water in your battery… I’M SURE SCOTTY CAN EXPLAIN IN CHEMISTRY TERMS. Use distilled water to fill it up. On the maintenance-free batteries, check your green eye, if your eye isn’t very green, then I would have your battery tested for free at a Jiffy Lube or Valvoline. Hope this helps. :)

  66. Mike says:

    All that white to greenish corrosion is acidic, apply a base to it. So, in everyday terms, put some baking soda (like “Arm and Hammer”) in a glass of warm water and pour it over the corroded terminals. It will fizz a bit; simply keep doing it until there is very little or no fizzing and your terminals are clean.

    Dry them off with anything disposable, like paper towels. Whatever you use, throw it out when done.

    Once the terminals are clean and dry put a coat of Vaseline over them. You should be good.

    Grease conducts electricity and if the top of your battery is dirty and greasy you can actually measure a low voltage discharge constantly happening across the top of your battery – so keep it clean.

    As for the best connection between the battery terminal and the connector, most auto parts stores sell a cheap tool to clean both the terminal and the connector. It’s basically a round wire brush for the connector and a doughnut-shaped wire brush for the terminal. For the terminals, you can also use the same tool many plumbers use to clean copper pipe before soldering it; you can find it in most Hardware stores.

    Avoid “old fashioned” remedies like maple syrup to coat your terminals. It doss coat the terminal and controls the corrosion, but you have a heck of a time with the ants I hear.

    Good luck.

  67. Jim says:

    I have used soda pop for years to clean battery terminals. The service man just told me today that baking Soda is a better choice because it is a base that neutralizes the acid. I have used grease over the years as well with some success. Not sure why the corrosion starts though. Any thoughts or suggestions on that? Must be the two different metals thing so the sacrificial “penny” makes sense. Once I found corrosion back into the cable for 6″. Now I just replace the cable if there is any sign of corrosion in the wire itself.

  68. Luxwing says:

    Who would have thought it would have been that simple? My battery light had been coming on two or three times a week for a few seconds each time, and then came on for almost five minutes on my way home today. I was afraid it was the alternator, so I took it to my local mechanics before getting home. He opened the hood and -lo and behold- my battery was covered in a white and blue conglomerate known as corrosion. o_o

    With a smirk, he tells me to get a Coke at the 7-Eleven and pour it on there when I get home.

    So I did.

    AND IT’S CLEAN! 😀 I couldn’t remove the cables since they were coated in the white stuff, but I was just sure to hose it all down after the Coke sat for five or six minutes.

    I will always be sure to keep a bottle of Coke in the garage! (-b^_^)-b

  69. Bubba says:

    I’m a chemistry professor and found Scotty the chemistry teacher’s message annoying too. No need to be so didactic. In fact, it’s this kind of attitude that turns many students away from science and engineering. Much of his message was unnecessary and some of it wrong, e.g. electrons moving at the speed of light.

    At any rate, I had to change my car battery today and was looking to verify that the white material on the positive electrode was lead sulfate and the blue material on the negative electrode was copper sulfate. I confirmed the answer elsewhere, but wanted to see how people clean away the material … I had to change it at a store and got a lot of bits on the engine so want to get rid of it. I’m troubled that a lot of lead is going down the drain and into our water supply. Anyways, thank you to the others for giving helpful, respectful info!

  70. DCM says:

    Pennies made prior to 1982 were 97.6% copper. After that, pennies were (and still are) made of almost all zinc with a copper plating. And it is completely legal to destroy a coin and it is illegal to destroy paper money.

  71. Bert says:

    My Expedition was completely dead this morning (I’m in Pennsylvania). It wouldn’t even take a jump, not even the “clicking” sound. My neighbor came out, poured a can of Coke on the terminals; they of course fizzed. She did it a few more times, then we put the cables back on and it took the jump immediately after we put the cables back on!

  72. Kirmie says:

    Don’t listen to all of Don’s advice. You should NOT add silicone grease to “all surfaces of the terminal and clamp.” Apparently nobody has informed Don that silicone grease does not conduct electricity and while it will protect from corrosion, it also has the same effect as the corrosion you are preventing.

  73. Brandy says:

    Yesterday, I came out to start my car and then it wouldn’t start. Then, AAA came out to give my car a jump and it wouldn’t start for the first 20 times. Finally, it started and I drove it to the nearest place where I could get a battery replaced. There was a ton of corrosion on the battery terminals. My husband came and cleaned off the terminals and replaced the battery. He then found out the connectors were corroded as well, so we had to purchase new connectors. The other thing he also discovered was that the battery wire was also corroding. I was wondering if anyone else discovered that when they changed their battery?

  74. Trace says:

    My car wouldn’t start today! I was upset thinking maybe my mechanic (who had my car just a few days ago to give me a tune-up) might have done something to make me come back and shell out more money! However, after looking at my battery cables, my boyfriend suggested it may be all the crude on the posts of my battery. I tried the baking soda and water suggestion, and later put petroleum jelly on the posts to slow future corrosion and VOILA!!!! My car started right up! Thanks guys, :) that saved me on going to a dishonest mechanic who probably would have agreed on me getting a new alternator… Clearly, I’m no genius mechanic, nor do I have knowledge about cars, but I must say – this is the trick!

  75. Luis says:

    People, forget about pennies; the Coke trick works great, just make sure to keep everything clean. And if you want to keep your battery safe from corrosion, just put some honey on the terminals after the cleaning. It’s a simple, easy, cheap and safe trick if you want to avoid trouble.

  76. N. says:

    People…forget about all the home remedies and do it like the article says to do it. Pennies, honey, Coke…etc.? For those of you that believe those things, more power to you. Just do the job right the first time (i.e. follow the articles instructions) and you’ll not have to worry about your battery or corrosion for a long time.

    Dielectric grease found at your auto parts store for less than 50 cents + baking soda and water + some brushes is all you need.

  77. Simon says:

    Wow Scotty. Do you shame-bomb your students the same way you came down on these list-members? How sad for your students. My high-school science teacher made science fun and interesting instead of scoffing and hurumphing and generally know-it-alling. Thank you for your service to our country. Now perhaps you should do a service to our youth and retire from teaching.

  78. Dave N. says:

    I used to put off such maintenance items thinking, “Who cares as long as the car keeps starting; I’ll take care of that next month.”

    My wife’s Toyota Camry, only one month out of warranty, had corrosion on the terminals; the folks at the shops kept telling her to get it fixed, she’d tell me and I’ll procrastinate.

    Then, it happened!! The whole alternator DIED instantly. Cost us a BUNCH due to rental cars, trips back to the town where it happened where the car was in storage, new alternator, motel bill, etc., and that was with me DIY. It seems the car was running everything electrical off the alternator to some degree except starting, obviously, until the alternator DIED. Never knew that would happen that quick.

  79. Dave N. says:

    Correction to someone who mentioned the ph values above:
    This is from Wikipedia,
    “In chemistry, pH is a measure of the acidity or basicity of an aqueous solution.[1] Pure water is said to be neutral, with a pH close to 7.0 at 25 °C (77 °F). Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline.”

  80. Raj says:

    Just tried warm water and baking soda, and used an old toothbrush for intermediate scrubbing. After two glasses of dousing with warm water baking soda solution (1 heaped teaspoon of baking soda to 3/4 glass of water microwaved for 40 seconds), it’s as perfect as can be.
    First, pour a little over the battery terminals one at a time as is.
    Second, when the bubbling reduces, disconnect the positive terminal first, then the negative.

    Take a small plastic cup filled with the warm water solution and dip the positive battery contact in the warm solution, leave it soaking whilst you take your old toothbrush and some more warm solution to scrub the now disconnected battery terminal. Dry positive terminal and contact with paper towels, napkins or even toilet paper if it’s all you got.

    Repeat the procedure for the negative side.

    Connect the cables in the reverse order.

    Smile; job well done.

  81. Jack says:

    The penny works. It has to be a newer type of penny, as they are made of zinc. Zinc is used as a “sacrificial anode” in high-end corrosion protection systems. It’s in every water heater, and wired to all ships. The penny will work best if the copper cladding is scuffed and the coin is electrically bonded to the terminal.

  82. Jason says:

    Some good tips here. I’ve been a mechanic all my life, and never heard the one about running the lights before cranking in cold weather. I’ll give it a try.

    Nor have I used a sacrificial anode. Zinc would be useful for this, copper would not, as many others have mentioned.

    Definitely clean with baking soda; the runoff from your cleaning won’t cause as much damage to other parts and the floor. I guess Coke would be an easier option if you’re stuck at the 7-11. Just wear protective equipment when handling Coke, and don’t take it internally. 😉

    If you’re stuck on the side of the road, another thing you might try to get going is to move the battery terminal on the post just a little. Depending on how tight they’re screwed down, this may or may not be possible. Twist them with a big pair of pliers or give a little whack with a hammer, being careful not to strike the plastic battery or short the positive terminal against metal on the car. The reason this helps is because it rubs the metal surfaces of the post against the terminal to move corrosion aside and bring more fresh post metal and fresh terminal metal into contact. If that works for you, of course the thing to do when you get where you’re going is pull the terminals off and give them a good cleaning and neutralizing.

    A can of spray battery terminal protector is a good idea; the Vaseline and grease never appealed to me since I’m probably the next guy to deal with taking them off and cleaning them.

    They make a nice little battery terminal puller, with hook arms that go under the terminal and a screw-in press shaft that goes on the top of the post. Even after you unscrew the clamps, they’re usually hard to remove. Prying with a screwdriver bends things up so you don’t get as full surface-to-surface contact when you put it back together. The puller exerts even force straight up. Here’s an example:


  83. Jacqueline says:

    Thank you ALL!!
    Today, my supremely reliable Nissan had no power whatsoever – no dash lights, no flashing LED on alarm, no central locking – in short, NOTHING.

    I cleaned the terminal posts and noticed that there was a white and green scum around the wires, but couldn’t get to them.

    A man came out to try to get the car going, but he was absolutely baffled and could not fix it, but did establish that there was nothing wrong with the battery or alternator.

    So now, thanks to your posts, I’ll give baking soda a whirl. Can’t do any harm – I have a dead car.


  84. Ernie says:

    How I got to the point of doing this is not important. It worked for me. Easy, no-brainer process. Had a reason to clean the engine compartment of my Dodge Ram. Sprayed it with Windex Outdoor Window and Surface hose end sprayer. After I rinsed, a difficult build up on positive terminal was gone and the connector was nice and shiny.

  85. Ron says:

    I work at Miller Electric. Grease and petroleum jelly are not good conductors of electricity. There is a grease made that will work. We use it on copper-to-aluminum connections.

  86. GC says:

    Scotty is right.

    Whether anyone believes he is annoying or not is irrelevant. What he was complaining about was that not only do so many people not know what they’re talking about, they’re spreading their misinformation as if it were gospel.

    I just had a battery terminal corrode enough to keep my car from starting. I had put *nothing* on the terminals when I put the battery in. It took three years for it to corrode that much. The moral is that if you try some trick to keep the corrosion away, you have to wait long enough for it to actually inhibit the corrosion before you can tell whether it worked or not. Six months or a year isn’t going to do it in most cases.

  87. Bob says:

    Scrub with a toothbrush and baking soda on dirty terminals, and clean the top of the battery too. Remove the negative and then positive terminals, and clean them with a wire brush terminal/post cleaning tool. I think that soaking a couple of inches of cable in a cup of baking soda solution is a great idea. Clean and dry all with water and a rag. Put anti-corrosion felt washers on your posts and then put the terminals back on, positive first and then negative. Tighten them up until they don’t wiggle, and then coat them with whatever grease you have. Whenever you look under your hood, wipe the top of the battery off with a rag or paper towel.

    Now as to the chemistry teacher, why bother; would he listen?

    Cheers, all.

  88. George. says:

    Odyssey batteries are better than Optima. They are the same battery that the U.S. army uses in the Abrams tank. Sealed gel and a ton of cranking amps. More than the 750 cranking you are used too.

  89. Usman says:

    Disconnect the negative terminal first.

    I want to correct Raj’s comment. While he is right about using baking soda solution for cleaning, he is wrong about disconnecting the positive terminal first.

    Disconnecting the positive terminal first will risk creating a spark if the wrench accidentally hits the metal part of the car.

    You should always disconnect negative terminal first in order to break the battery’s electrical path, then you can safely disconnect the positive terminal.

    Then, you can reconnect the cables in the reverse order.

  90. HenCho says:

    I used:

    Baking soda + water = thick paste + toothbrush = brushed the posts and the clamps + 5 min + water = cleaned up the mess + dry paper towels = clean and dry posts/clamps + thin coat of Vaseline on posts/clamps + $3 posts cover from Advance Auto Parts = WIN!

    This was two days ago, and so far so good.

    **Remember: negative off first and on last.

  91. Mike I says:

    If you do use Coke or something else like that to clean your battery terminals, FLUSH EVERYTHING with lots of clean water when you are done!

    I’ve seen several cars where the metal around and under the battery casing has been badly rusted from this trick. Both Coke and battery corrosion are acidic; together, they’re just nasty as all get out!

  92. Lola says:

    ALWAYS, ALWAYS, ALWAYS wear those safety goggles when working on the battery. I worked at the Eye Doctor’s for awhile and will never forget the handsome young daddy who came to the office for a re-check after having one eye destroyed because his battery exploded when he tried to clean it. He was cringing when I looked at him because he was so self-conscious of how he looked and all I could imagine was how he now had to go through life with vision in only one eye, which would affect his whole future.

  93. Dana says:

    My car wouldn’t start yesterday so I cleaned the terminals with what I had (a screwdriver). Today I stopped at the store for baking soda and again my car wouldn’t start. I banged on it with a wrench and more corrosion had already built back up. It started and I made it home. I used the baking soda, but haven’t had to leave yet. I hope it works.

  94. Don says:

    The cables are copper and attach to the lead clamps, therefore putting a copper penny in to stop corrosion is pointless since there’s already copper there. Coke has carbonic acid, so it does not neutralize the sulfuric acid in the corrosion, and has been proven to be bad to use.

  95. Linda says:

    My battery was completely dead. I did not have the tools to loosen the terminal cables. In desperation, I poured a mixture of baking soda and water on the outside of the terminals. I hooked up the battery jump-starter and tried starting the engine. It purred on the first try. I am over the moon!

  96. Kimberly says:

    Alka-seltzer with a half cup water worked for me. Since it is made up of mostly sodium bicarbonate, it is basically the same as baking soda. Good luck all.

  97. Howell says:

    I find it interesting that, after five years of this article being posted, the technology has not been integrated that allow users to up/down vote comments; such as YouTube has had for several years.

    If you guys were so offended by Scotty, that science teacher’s post, I’d hate to see what you would do with a real troll (or whether these comment sections even have the technology to deal with that situation). That’s why YouTube is so much better; there’s probably 10,000 videos on how to do this, which is better than reading sometimes.

  98. Mike says:

    Hmm. If Coke can clear away corrosion on battery terminals, it’s time that I turn to flavored water.

  99. Aaron says:

    Greetings Everyone!
    From the information I found, zinc will act as a sacrificial anode for lead (the zinc pennies). Its potential is more negative. However, please remember that surfaces have to zinc on lead for this actually to protect your terminal. Making sure that there is not grime or ash residue blocking a connection is important.
    The reaction can be blocked the exact same way the oxidized terminals block electric flow to the cables, so make sure they are clean! Baking soda is a wise choice for cleaning.
    Coating the cables and terminals in grease is a good way to prevent oxidation. When the cables are attached to the terminals, the grease will usually get pushed out of the way by the metal. If you are skeptical, just don’t put grease where the metal joints touch; you won’t be sacrificing much protection to the connectors by doing so.

  100. Tim says:

    LOL at the “defacing US currency” comment.

  101. Dexter says:

    Thanks to this site and everyone’s help! We lay-people thank God for people like you who give the soundest advice. Cheers mates. ♥

  102. Spike5 says:

    I usually never leave a comment on things like this. Usually I just read the pertinent information and move on, but I just had to say – THANK YOU.
    The posts above were all very helpful and I ended up using several of the methods mentioned in combination. Mostly though, reading this blog created inspiration. Instead of me just putting the work off until another time, I went out and tackled my battery corrosion terminal problem and was done in about a half hour. One recommendation that I have is to put a fresh chew in before you start. You’re not gonna want to put anything near your mouth during this.
    What I did;
    I first put on protective eye wear.
    Took the cables off, negative first.
    I ended up disassembling the positive cable end completely since it had corrosion throughout its many parts. I actually submerged the positive cable end assembly completely in a can of baking soda and hot water.
    Then I went to town on everything battery related with the baking soda solution and an old tooth brush.
    I then decided to remove the battery, hold down bracket and completely brush all parts of it with the baking soda and hot water solution.
    I wire brushed the terminals a little bit.
    I also used one of those special battery terminal cleaning brushes, making sure not to over-do it with that tool as mentioned by an earlier poster.
    Then I applied a small amount of petroleum jelly just on the bases of both positive and negative terminals.
    I then reassembled everything, making sure to reinstall the positive cable first.
    I then tightened everything up, including the battery hold-down bracket.
    I then sprayed WD-40 very sparingly on top of both terminals and wiped off any excess and at the same time, wiped as much of the battery clean as I could.
    I then put the red rubber boot back over the positive terminal assembly and I was done.
    Oh yeah, I forget to mention, the reason I need to do this was that my battery warning light came on and when I looked at my battery, the positive terminal looked like a whitish/gray Chia pet. The corrosion was very apparent.
    When all was done, I started the car up and no more battery warning light!
    Let’s hope this is the solution to my problem. We shall see. My alternator is only a year and a half old and came with a three year warranty so I think I’m done.
    Again, thank you all.

  103. Fnorgby says:

    Here’s an expensive and not recommended solution: Stuck in the middle of nowhere with no baking soda or Coke or anything… I did have some Zegrid — similar to Prilosec. Zegerid capsules (not tablets!) contain sodium bicarbonate –each 20 mg capsule has a gram of sodium bicarb. Omeprazole alone won’t do it — probably doesn’t do anything. Omeprazole-bicarb is what did it. Up and running and could get to an auto supply store.

    Zegerid is more expensive than Prilosec, which is already expensive. Six pills probably cost me $4, but it’s better than waiting for AAA.

  104. Fred says:

    Great posts to all. This is what I do for my batteries. Supplies are nitrile gloves, safety glasses, baking soda, hot water, a toothbrush and electrical terminal grease. Clean with baking soda and water, wash down with soapy water then rinse with clean warm water, apply a thin layer of terminal grease to each post and re-connect clamps and you will be good to go.

  105. Paul says:

    I just cleaned the terminals with a damp rag and used medium sandpaper to do the job. The sandpaper works just fine.

  106. Jimmy says:

    I wonder if Scotty’s students noticed that he did not offer any useful solution for this common problem that affects lots of folks in the real world.

  107. Mungo says:

    Scotty is right on the money!!! Posting incorrect information when it comes to basic science is worse than NO information. The point is, if you are going to give advice, make sure the science is correct. If you aren’t sure, don’t post it… simple! Propagating myths doesn’t help our kids.

  108. Paul says:

    Felt corrosion disks are an excellent idea, as is lightly scouring the cleaned terminals and the inside of the connections with a terminal scrubbing tool, both cheaply available at any auto parts store. Baking soda and water works to clean the big stuff off, as does Coca-Cola (which contains phosphoric acid, the main ingredient in commercial de-rusters). Once the terminals are clean, though, I use a light application of Sanchem’s NO-OX-ID to more or less stop the corrosion permanently. This very old, excellent product contains a mixture of anti-corrosive agents mixed with beeswax to form a virtually permanent protective layer that does not interfere with conductivity; I would recommend it over the grease or petroleum jelly suggested by the article.

  109. Trishanu says:

    The water should be warm to hot.

  110. John says:

    I bought two new terminal clamps and my car runs better. My friend who’s dad is a mechanic told me it will run better because it was running off the alternator. Is this true?

  111. Bazza says:

    I find the attacks on Scotty a bit over the top guys. Having once upon a time taught adults about science, who had failed primary school (just kidding, but they had little education), I found ways of explaining the basics to these people and they mostly went on to interesting jobs and further education, so I figure I must have something right. So, I found Scotty’s post quite acceptable and he is right too. There is a great deal of misunderstanding of the basics here. While electrons can move at the speed of light, they tend not to unless in a perfect vacuum with little to no other fields working on them. In conductors, they do move slower. This ignores the whole quantum debate as it is just too much for this discussion. Generalizing about electron speed is acceptable given the level of misunderstandings in this forum, but he’s generally right. Criticizing him shows they misunderstood him and are foolish; to insult him is just plain trollish. He certainly went over most people’s heads, but that’s because he is correct about the level of science education and full marks to him for pointing that out. We, in other countries, tend to think of your country as lacking in education, but unfortunately, so are ours as our politicians try to emulate your politicians. What a sad situation. My only criticism, Scotty, is you should have assessed your audience better and written accordingly. I suppose I’ll get it now.

  112. Pritam says:

    Thank you for these useful suggestions.

    One clarification – I feel you should remove the wires in the reverse order. That is, remove red + first followed by black -. And, while replacing them, put the negative on first then the positive one.


  113. Tony says:

    I have corrosion on my terminals, and I have the red and green circles to prevent this on the terminals.
    So they do not work. Here in FL, a lot of heat and rain does help this develop.
    Do check your battery water level while cleaning up the terminals.
    I have related low battery water levels, and a battery that is going bad to having corrosion develop in the past.
    Baking soda worked great for me and used the high heat purple grease after the terminals were secure.
    As the battery has been disconnected, do remember to reset your clock or you will be running on the wrong time until you do.

  114. Tim says:

    No, Pritam. All due respect, you are mistaken. There is a reason for removing the Neg-Black cable first. Putting a wrench on the Red+Pos cable and touching the other end of tool to any ground spells trouble. You’re far less likely to have a problem with Black-Neg clamp first.

  115. Tim says:

    Good ole American ingenuity & folklore on the battery/cables with coke and baking soda. Also, if you do run into a weak cell battery, try to drop an aspirin (strong Mg) into the weak cell; it should work until you can afford a new or used battery. It reinforces the well cell, plus rejuvenates the acid in the battery cell. This was passed on to me by Rickie Moore and Uncle Cleo Tolbert; both originated from northeast AR.

  116. Millie says:

    Hi. Does anybody know if I can use the baking soda and water method without disconnecting anything?
    I am trying to avoid messing up some code older car.

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