How to clean up a battery leak in a flashlight

May 28, 2006 7:02 AM

When trying to change the batteries in my maglite after a long period of neglect, I found that the cap wouldn't unscrew. After persuading it open with a pair of mol-grips, I could see that one of the batteries had leaked and there was a big grey corroded-looking stain on the inside of the battery compartment. Is there any way I can clean this up, or should I bid farewell to my trusty torch? The battery is a D cell alkaline.
posted by primer_dimer to home & garden (7 answers total)

Sure. The potassium hydroxide (a base, hence the name 'alkaline battery') has leaked from your batteries (it's a wet paste inside the battery) and dried in your flashlight.

It will dissolve in water. You can use some slightly acidic water to neutralize the base - add a little vinegar or lemon juice or something like that to your cleaning solution, don't rub that grey stuff in your eyes, wash your hands thoroughly when you're done, etc.
posted by jellicle at 7:14 AM on May 28, 2006

Send it to a Mag-Light service center. Mag Instrument has some of the best customer support anywhere. They'll fix it or send you a new one.
posted by Etaoin Shrdlu at 7:29 AM on May 28, 2006

Thanks jellicle, I had to soak the pieces in lemon juice to get the grey gunk off, but it worked in the end. Science, ho!
posted by primer_dimer at 9:08 AM on May 28, 2006

I think cream of tartar will also work very well for this kind of thing. It's tartaric acid already half-diluted with potassium hydroxide, so presumably, it would mix happily with more of the same stuff.

Always combine bases and acids in a well-ventilated area, preferably outdoors, and don't breathe any fumes. It's best to use gloves and glasses. Battery goop won't kill you, but it can burn you pretty good if not immediately washed off after exposure.
posted by Malor at 11:52 AM on May 28, 2006

Always combine bases and acids in a well-ventilated area, preferably outdoors, and don't breathe any fumes.

This is a good way to remember how to mix water and acid (author unknown):

"May her rest be long and placid,
She added water to the acid,
The other girl did as she oughter,
She added ACID to the WATER."
posted by mlis at 7:08 PM on May 28, 2006

Over the years Ive had luck sending it all to the leaking battery's manufacturer... It didn't 'ask' I just sent and always got the stuff back and cleaned up. Instead of tossing the MagLight spend a couple of bucks on postage and give it a shot.
posted by freeflytim at 7:20 PM on May 28, 2006

Cream of Tartar = Baking Powder (not soda)
posted by nomisxid at 4:49 PM on May 30, 2006