Cleaning Alkaline Battery Corrosion From Toys And Household Electronics

Crusty batteries and crusty battery compartments…oh my.

I got started on a new project with an electronic toy cow that runs on two AA alkaline batteries. The first blip I encountered was that it would not power on and moo at me. Unscrewing and opening its battery compartment revealed a gunky interior from the batteries having leaked and dried up in it many moons ago. Replacing the batteries did not help.

Not wanting to write off this fine bovine specimen for part-harvesting just yet, I snipped the leads to its battery compartment and hooked them up to a fresh battery holder. A firm press of the cow’s yellow nose elicited a deep howl from the speaker grill in its forehead. This confirmed that the points of failure were the battery compartment’s contact plates and terminals, due to the corrosion and residue preventing any conductivity between the batteries and the rest of the circuit. Considering that, I determined that it was still possible to give the cow a new lease on life with a good cleaning of its battery compartment.

Battery Leakage

Battery leakage happens as a battery naturally discharges over time, and in doing so releases a bit of hydrogen gas within; this creates internal pressure that results in the battery eventually bursting. The battery’s electrolyte (potassium hydroxide in the case of alkaline batteries) leaks out and upon being exposed to air, mixes with carbon dioxide to form potassium carbonate which is capable of corroding its surrounding area and continues to spread, further damaging the host electronic. A battery that has begun leaking should be removed and disposed, because it is bad for you.

My Cleaning Trick

There is a simple go-to treatment that I use to “fix” simple electronics that suffer from this ailment: dabbing or soaking in white distilled vinegar (or something similarly acidic) — for leaks and residue from alkaline batteries.

On the flip side, with mildly acidic and acidic batteries you would need something basic such as a paste made from baking soda and a dash of water.

You can find out what battery type you are dealing with by checking its label/package or by looking it up. In both scenarios, the substance being administered to the corroded/blighted areas neutralizes the leaked out electrolyte.

In some cases no amount of cleaning will work when there is too much damage from corrosion.

Disclaimer: If you try this out, I am not responsible for damages. I would also like to add that I have only used these methods with small, simple electronics that run on typical batteries. There are comparable solutions out there for things like car batteries and that is beyond my area of experience/knowledge. I generally don’t advocate working with things that can cause severe electrocution.


Since the cow lives off alkaline batteries, white vinegar it was. I poured some into a small dish. Here I used the lid of a jar I threw out. Don’t use anything that you’ll use again for your food!

Then, using Q-tips soaked in white vinegar I dabbed the battery compartment’s springs, contact plates, and terminals to clean them:

Important: Safety, safety! Use gloves or at least avoid touching the stuff with your bare hands, don’t breathe it in, don’t touch your face while working, and thoroughly wash your hands and clean spills on your workspace afterwards.

After going over these metal parts a handful of times until I was satisfied with the results, I used dry Q-tips and paper towels to tidy up the area:

Sometimes it is not possible to get 100% of the corroded gunk out of the way, especially if you can’t reach or thoroughly treat both sides of the battery compartment. Some spots are simply stubborn. The more stuff you can clean off the better, but it doesn’t have to be perfectly scoured.

Did It Work?

I popped in a fresh pair of batteries into the newly cleaned battery compartment and hooked up its terminals to the rest of the cow using alligator clip test leads.

Rejoice, for it began to play the melody of Oh Susannah to me following the smack of a button.

Share your thoughts