How to Get a Corroded Battery Out of a Mag Light

Potassium hydroxide is a strong base that can leak out of alkaline batteries and dry up inside your flashlight—even causing the battery to stick. Mag, the manufacturer of Mag Lights, does not warrant against battery leakage. However, according to their website, if your batteries are Eveready, Duracell or Ray-O-Vac, you can send the flashlight back to Mag and they will repair or replace it at no charge. If you’d rather fix it yourself, the strategy is to break the adhesion by neutralizing the leaked substance, using acid on an alkaline battery and a base on an acid battery.

Things You'll Need

• Sodium bicarbonate
• Lemon juice
• Vinegar
• Cola
• Cotton-tipped swab
• Paper towels
• Old toothbrush
• Pencil eraser

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Instructions

• 1

  Dissolve as much sodium bicarbonate (baking soda) into a glass of water as you can, if your batteries are acid. If they are alkaline, pour one part lemon juice or vinegar into one part water. A gray stain is likely alkaline while white powder is likely acid. You may want to try both alternately if you’re unsure.

• 2

  Unscrew the back of the flashlight and pour the solution in by small amounts around the area where the battery seems to be stuck to the flashlight. If you can’t even get access to the inside of the flashlight, then you still have the option of sending the flashlight in to Mag (see Resources). You may need to add more solution if the battery doesn't slide out after given a little time to react. Don't jolt the flashlight, risking a splash of acid/base on yourself or elsewhere, as the problem should be solvable chemically. If the battery doesn't yield, try the opposite solution you tried before. In other words, if you tried pouring in a base, try an acid (for example, lemon juice), just for the sake of safely moistening the spill. And if you tried acid, pour in a base (a baking soda solution). You may need to nudge the battery to get the solution to react fully with the spill. Once you dislodge the battery, throw it in the regular garbage inside a plastic bag and go to the next step.

• 3

  Use more of your acid or base solution to scrub away the stains inside the Mag Light, perhaps with the aid of an old toothbrush. Use cola on cotton-tipped swabs or paper towels to clean the battery contacts inside the flashlight. Polish contacts with fine sandpaper as an alternative. Rub a pencil eraser on white residue to dislodge it.