Manual / Frugal maintenance
How to Clean Corroded Battery Terminals Safely
White or green crust on the terminals adds resistance and causes slow starts. Clean it in ten minutes with baking soda and a brush.
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That fluffy white or blue-green crust on your battery is corrosion, and it is one of the cheapest no-start problems to fix.
Safety first
Wear safety glasses and rubber gloves. Battery acid irritates skin and eyes, and the crust contains it. No smoking or open flame nearby.
Steps
- Engine off, key out.
- Disconnect negative (−) first, then positive (+). This keeps your wrench from shorting to the body.
- Mix a paste: 1 tablespoon baking soda in a cup of warm water.
- Scrub posts and clamps with an old toothbrush or a terminal brush. It will fizz, which is the acid being neutralized.
- Rinse with a little clean water and dry completely with a rag.
- Reconnect positive first, then negative. Tighten until the clamps don't twist by hand.
- Optional: a thin coat of dielectric grease or terminal protector.
Clean terminals but the battery still struggles? The problem may be inside. The Easy Battery Fix guide covers testing and reconditioning methods for lead-acid batteries. We wrote up a plain-English review.
See our review →Why it keeps coming back
Repeated corrosion on the positive side often means overcharging or a seeping post seal. If the case is cracked or bulging, replace the battery.
Want more do-it-yourself battery care? Take a look at the guide we reviewed.
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