Nancy asked: A battery corroded in the bottom of a flashlight. How can I remove it without ruining the flashlight? This is a small, plastic flashlight that uses 2 AA batteries. I left one batter in the bottom for two year, and now it is corroded. New batteries do not work in this flashlight. How can I clean out the corrosion without damaging the working mechanism of the flashlight? Thank you.
Corroded batteries can be a real nuisance to remove and clean up. But when it comes to saving the flashlight, it is often worth the effort. The first step is to remove the battery while keeping it as intact as possible. Then, it’s time to tackle the mess left behind. Here’ s what to do:
You Will Need:
- Rubber gloves
- Bottle brush
- White vinegar
- Dowel rod (small enough to fit in the flashlight, but as large as the diameter of the battery)
- Drill (optional)
- Piece of wood or hard surface
Steps to Clean Out the Battery and Corrosion:
- The first step is to put on gloves and eye protection. Battery corrosion is very caustic and touching it could give you chemical burns.
- Remove the corroded battery. If both ends of the flashlight are removable, this will be quite easy. In this case, just place the flashlight on a piece of wood or other hard surface.
- Place a dowel rod in the flashlight and on top of the corroded battery.
- Tap the end of the dowel rod with a hammer to knock the battery loose.
- Remove the battery and dispose of it properly.
- If both ends of the flashlight cannot be removed, it will be slightly more difficult to remove the old battery, but it can be done. One method is to use a drill.
- Use a drill with a long bit and screw it into the end of the battery.
- Once the bit is secure in the battery, pull it out. It may take some maneuvering, but the battery should come out with it.
- Next, you will need to remove the corrosion from the interior of the flashlight.
- First, inspect your flashlight to determine where the electrical parts are. Usually they are located right around the bulb, not near the battery compartment.
- If the electrical parts are located near the bulb (separate from the battery compartment), you can use a mild acid (vinegar) to loosen the corrosion and scrub it away. This works on both alkaline and acidic batteries. (Skip to step 16 if the electrical parts are not separate from the battery compartment.)
- Pour some white vinegar into the battery compartment. You only need a little; just enough to wet the corrosion. Don’t be surprised if it starts fizzing; that means you had alkaline batteries.
- Use the bottle brush to scrub the inside thoroughly. If you don’t have a bottle brush, you can use a cleaning cloth wrapped around a piece of wire, such as an unfolded wire hanger if needed. Do not put your hand into the flashlight; you may get chemical burns from the corrosion.
- If necessary, allow the vinegar to soak in the flashlight for a few minutes, but no more than five minutes total.
- Rinse thoroughly with clean water.
- Dry it as much as possible with a soft towel and allow it to air-dry completely before use.
- If the electrical parts on your flashlight are not separate from the battery compartment, do not pour vinegar into the flashlight as it might seep into the electrical area. Instead, wet a cloth with the vinegar and wring it out so that it is only damp, not dripping.
- Wrap the damp cloth around something sturdy like an unfolded wire hanger or a stick.
- Put on rubber gloves.
- Use the cloth to clean out the corrosion.
- Rotate the cloth to a clean area as you remove the corrosion.
- Continue wiping out the corrosion until it is gone.
- Use another cloth that is damp with plain water to wipe out the inside to remove any remaining residue.
- Allow the flashlight to air dry fully before putting in new batteries.
Additional Tips and Ideas
- Battery acid should not come in contact with the skin. Protect your skin with rubber gloves while cleaning corroded batteries.
- Some have found Coca Cola effective for removing corroded batteries. Simply soak the battery in the cola then tap lightly until the battery falls out.
- If the battery is not too badly corroded, it may be possible to remove it with vigorous shaking.
- Baking soda has also been found effective for removing corroded batteries. Simply pour some soda into the flashlight, then shake it slightly to distribute the powder. Next, tap the sides lightly to dislodge the battery and remove it.
- The primary goal is to remove the corrosion, not to neutralize it. If you have alkaline batteries, using vinegar will neutralize the corrosion (which is just an added bonus) and the chemical reaction will help to jar the corrosion loose so it can be removed. For acid corrosion, the vinegar will dissolve it so that it can be removed, which may be a more effective method. If you want to neutralize the acid corrosion, you would have to use an alkaline material, such as baking soda dissolved in water.
Your tip on using the drill bit is a great solution.
It is important advice for parents that children need to know the hazards of corroded batteries. We have so many toys now days that take batteries. Kids try to change batteries themselves but rarely know of the dangers.
Thank you for detailing this out.
Run hot water over the end of the flashlight (not into it), and the battery will just slide right out.
When not using battery operated devices, place them so that they do not make a complete circuit. Place both negative or positive ends facing each other, which should help to prevent battery corrosion. I have never had batteries corrode when placed this way.
Hot water worked the best and was the easiest. I also used a wire brush to clean the tubes. Thanks, Jim
Will cider vinegar do the same?
YES, for the alkaline batteries, typical C, D, etc. But slower than a good strong white vinegar.
I have a digital camera (HP-315) with corroded batteries inside. I can’t even open the battery compartment. Any suggestions?
WD-40 also does a great job loosening up those stuck batteries.
Before trying the drill bit, I poured vinegar into the battery case and let it sit a few minutes.
The batteries came out with some firm rapping of the case.
The Computer Geek says
I am repairing my dad’s old and broken flashlight. Hopefully it works!
Thanks a lot for the information; appreciate it.
Note that if there are any electronics in your flashlight (for example around the positive terminal, or possibly if it has flashing effect or different levels of brightness), don’t use vinegar on that part! Alcohol only.
I have a Smith & Wesson flashlight and the batteries have leaked inside. I am trying the vinegar first because I don’t want to toss it.
I have an item where the batteries have corroded and the plastic hatch door is stuck. I tried soaking it in vinegar–it didn’t work. I can’t move the slide to open it; any suggestions? Thanks.
I don’t have a drink, so used a cork screw on the battery, then a brush for the tube and water to clean up the rust on the lid. I made sure not to introduce any water into the torch. Thanks.
I used this advice to clean up the contacts on a musical nightlight. The battery compartment is very narrow so I used cotton buds and cotton wool to dab vinegar on and polish it off. It took a few applications, but it worked and the nightlight has sprung back to life. Thank you!
Years ago you could send the damaged item to the battery manufacturer and they would repair or replace the item, but I doubt this is still the policy with our new, money hungry corporations.
The problem I have with this even if they still do R & R your corroded item, is I have no idea which brand is down my flashlight tube.
Thank you very much! I cleaned a pretty sorry-looking Sony CD player, using vinegar-soaked Q-Tips to access the narrow battery compartment, and it functions perfectly now.
Safety First says
NEVER drill into a battery. It’s full of liquid electrolyte, which is very toxic and can cause PERMANENT BLINDNESS if it gets in the eyes. It can cause painful chemical burns on the skin. The liquid can get everywhere and can affect children and pets if they come into contact with it. Just throw the flashlight away; it is not worth the risk! Also, removing spills on exposed skin with vinegar to “neutralize” it will just trap chemical into the skin, making it worse. I know from personal experience. It is much better to flush with soap and water until the chemical is removed from skin.
Well I hope one of these solutions works. I am trying to get four D batteries out of a Mag Light that my best friend’s Dad used when he drove a truck. The end was so hard to get off because it had corroded so bad; had to use two pipe wrenches to get it off. These batteries have been in this flashlight almost 10 years. They are corroded to the sides tight to where I drilled down the middle and chipped the battery out a little bit at a time. Remember to wear protection, rubber gloves, and I used a faceshield. Thanks and wish me luck. Will let you know.