How to Remove Corroded Batteries From a Maglite

By johnmcgee

Mag Instrument Inc. manufactures the Maglite heavy-duty flashlight. As with any household item that gets intermittent use, the alkaline batteries inside the flashlight may leak if not changed out regularly. The leaked material may chemically join the batteries to the material Mag uses for the flashlight casing. If you can’t remove the batteries mechanically, you can resort to a chemical strategy. Neutralizing the corrosion should allow stuck batteries to come out easily.

Things You'll Need

  • Flathead screwdriver
  • Hex wrench set
  • Lemon juice
  • Vinegar
  • Baking soda
  • Light oil, such as automotive aerosol lubricant
  • Cola
  • Fine sandpaper
  • Cotton swab

Step 1

Unscrew the head of the Maglite, exposing the bulb. Unscrew the light bulb.

Step 2

Lift off the on/off button with a flathead screwdriver. Insert a hex wrench (usually 2mm) into the hole that was underneath the button. Insert it all the way down. Unscrew the switch mechanism and slide it out the head of the flashlight.

Step 3

Set the flashlight on its tail, fill it as high as you can with lemon juice or vinegar and let it sit for a half hour. The tail cap, still in place, will act like a cork, keeping the fluid in.

Step 4

Empty the reacted solution into the sink. This should be safe, since any alkaline paste coming out will be neutralized.

Step 5

Try to remove the battery mechanically. Remove the tail cap and push the batteries out, using a broomstick if need be. Lubrication may help if the batteries are swollen. Vegetable oil may work, but an automotive aerosol lubricant may work best. Use enough to get into all spaces between the battery and casing.

Step 6

Put the tail cap back on and repeat steps 3, 4 and 5 if the battery is still stuck. If the second try fails to dislodge it, proceed to Step 7.

Step 7

Fill the flashlight again, but this time with a mixture of baking soda and water, which may help soften the corrosion as well as clean up the mess inside. Putting too much baking soda in the mixture is preferable to putting in too little. Again, let it sit for half an hour.

Step 8

Empty the solution into the sink and try to dislodge the battery again. In the unlikely event that you still can't get it out, contact Mag (see Tips.)

Tips & Warnings

  • After getting the battery out, use fine sandpaper or cotton swabs dipped in cola to clean the flashlight's battery contacts. Use baking soda and water to clean up general corrosion. Let the flashlight dry out before reassembling it. Reassemble the flashlight in the reverse order that you disassembled it.
  • If the batteries will not come out and they are Duracell, Eveready or Ray-O-Vac, send the Maglite to Mag for a free replacement (see Resources).