Over at Wirecutter, my friend and colleague, the Power Queen Sarah Witman got up close and personal with that whitish, crusty mess that often overtakes your alkaline batteries (you know what I'm talking about). "Even the best household batteries are prone to rusting, corroding, and leaking chemicals, especially when they're exposed to moisture or heat," she explains. "Fortunately, there's a simple way to clean up battery discharge, and chances are good you already have everything you need at home."
From there, Witman walks you through some cleaning tips that will not only keep you safe (that stuff's toxic), but also prolong the life of your electronics, so the battery acid doesn't keep eating away at them.
Most household batteries contain base chemicals, whether they're single-use (alkaline) or rechargeable (nickel-based) batteries, so acids will neutralize them. After making sure the device is powered off, use a cotton swab to apply a few drops of lemon juice or vinegar to the affected area. The whitish, crusty discharge should start to fizz and disintegrate.
How to Get Rid of Battery Corrosion [Sarah Witman / New York Times]
Image: Mathieu BOIS / Wikimedia Commons (CC 1.0)
Full disclosure: I also write for Wirecutter.