Little is more frustrating than grabbing a battery-powered tool, flashlight, or kid's toy and finding that it doesn't work except opening up the battery case to find a corroded mess. That corrosion must be cleaned away from the contact posts to give the item any chance of working again even with fresh batteries.
If the problem is caught early, with just a few items from your pantry, there is hope that you can clean away the corrosion and get things powered back up.
Chemicals such as sulfuric acid that are exposed during battery leakage are caustic and corrosive and can damage eyes and burn skin. Protective eyewear and gloves should be worn when handling leaking batteries or attempting to remove corrosion from battery compartments.
Do not attempt to clean leaking batteries. They should be removed from the device, placed in a plastic bag, and disposed of properly following waste guidelines in your community.
Equipment / Tools
- Old toothbrush or small bottle brush
- Small bowl
- Pencil eraser
- Distilled white vinegar
- Fresh lemon juice
- Cotton swabs
- Baking soda
- Newspaper or disposable cloths
- Paper towels
How to Clean Alkaline Battery Corrosion
Alkaline batteries—AAA, AA, C, D—are the most commonly used non-rechargeable batteries in toys, household gadgets, and flashlights.
Before removing the corroded batteries or attempting to clean the device, always put on safety glasses and gloves. Protect work surfaces with newspaper or disposable cloths and work in a well-ventilated space.
Remove the Batteries
Wearing gloves, remove the batteries from the device. Do not attempt to clean the batteries and dispose of all of the batteries and even those that don't look corroded. Since batteries can cause soil contamination, place them in a plastic bag and dispose of them following the waste guidelines in your community.
Neutralize the Battery Corrosion
Scrub Away the Corrosion
Depending on the level of corrosion, use a cotton swab or small brush to scrub away corrosion residue from the corners and contact points in the battery case.
Dry the Battery Case
Use a paper towel to thoroughly dry the battery case and contact points.
Polish the Contact Points
If any corrosion remains on the battery contact points of the device, mix a tablespoon of baking soda and a few drops of water in a small bowl. Dip a cotton swab in the mixture and rub the contact points. Move to a new cotton tip as any rusty residue is transferred. When no more residue is transferred, carefully wipe the contact points with a clean cloth to remove any traces of the baking soda.
The contact points can also be polished with a pencil eraser to remove traces of corrosion residue.
Insert New Batteries
Once you are certain that the battery case is completely dry, insert new batteries. Do not mix old and new batteries.
How to Clean Nickel Cadmium Battery Corrosion
Nickel Cadmium (NiCad) batteries are rechargeable. While less prone to leakage than alkaline batteries, they are more corrosive and the clean-up is handled differently.
Remove and Dispose of Batteries
Remove the batteries and dispose of them following waste guidelines in your community. Do not attempt to recharge batteries that have leaked.
Clean the Battery Case and Contact Terminals
Sprinkle the inside of the battery case with dry baking soda to neutralize the potassium hydroxide in the corrosion. Empty the powder into a trash can for disposal.
Make a Baking Soda Paste
To remove any remaining corrosion on the battery contact points of the device, mix a tablespoon of baking soda and a few drops of water in a small bowl. Dip a cotton swab in the mixture and rub the contact points. When no more residue is transferred, carefully dry the contact points with a paper towel.
Insert New Batteries
Insert new batteries into the device and charge, if necessary.
How to Clean Lithium Battery Corrosion
It is very unusual for lithium batteries used in cell phones and laptop computers to leak. But when it happens, it is very dangerous and highly combustible. Do not attempt to clean lithium battery corrosion. Consult a hazardous waste professional.
Tips to Prevent Battery Corrosion
- Store batteries in a cool, dry place.
- Do not attempt to use expired batteries
- Remove batteries from devices that will not be used regularly.
- Do not mix old and new batteries in devices.
"Sulfuric Acid Poisoning Information". Mountsinai.Org, 2021, https://www.mountsinai.org/health-library/poison/sulfuric-acid-poisoning.