How to Clean Corroded Batteries from a Flashlight


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 keep it as intact as possible. Then, it’s time to tackle the mess left behind. Here’ s what to do:

You Will Need:

  • Towels
  • Bottle brush
  • White vinegar
  • Dowel rod (small enough to fit in the flashlight, but as large as the diameter of the battery)
  • Hammer
  • Drill (optional)
  • Water
  • Rubber gloves (optional)
  • Piece of wood or hard surface

Steps to Clean Out the Battery and Corrosion:

  1. The first step is to 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.
  2. Place a dowel rod in the flashlight and on top of the corroded battery.
  3. Tap the end of the dowel rod with a hammer to knock the battery loose.
  4. Remove the battery and dispose of it properly.
  5. 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 to use it a drill.
  6. Use a drill with a long bit and screw it into the end of the battery.
  7. Once the bit is secure in the battery, pull it out. It may take some maneuvering, but the battery should come out with it.
  8. Next, you will need to remove the corrosion from the interior of the flashlight.
  9. To accomplish this, we will use a mild acid (vinegar) to loosen the corrosion and scrub it away.
  10. Fill the flashlight with a small amount of vinegar.
  11. Use the bottle brush to scrub the inside thoroughly.
  12. If necessary, allow the vinegar to soak in the flashlight for a few minutes, but no more than five minutes total.
  13. Rinse thoroughly with clean water.
  14. Dry it as much as possible with a soft towel and allow it to air-dry completely before use.

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, shake it slightly to distribute the powder. Next, tap the sides lightly to dislodge the battery and remove it.


  1. 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.

  2. Run hot water over the end of the flashlight (not into it), and the battery will just slide right out.

  3. 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.

  4. Hot water worked the best and was the easiest. I also used a wire brush to clean the tubes. Thanks, Jim

  5. Will cider vinegar do the same?

  6. I have a digital camera (HP-315) with corroded batteries inside. I can’t even open the battery compartment. Any suggestions?

  7. WD-40 also does a great job loosening up those stuck batteries.

  8. 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.

  9. The Computer Geek says:

    I am repairing my dad’s old and broken flashlight. Hopefully it works!

  10. Thanks a lot for the information; appreciate it.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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!

  16. 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.

  17. 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.

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