Q. What causes corrosion of car battery terminals, and what’s the best way to deal with it?
A. The sulfuric acid used in car batteries produces hydrogen gas, which is the primary contributor to corrosion. Small amounts of gas are released that combine with the heat, dirt, oil and humidity in the air, which forms the corrosion on battery cables and terminals. If you don’t get it off, it can cause problems, such as trouble starting the vehicle or the electrical supply losing power while you’re driving.
To clean the battery, first remove both terminals with a socket wrench, starting with the negative (black) cable. The white crystals of the corrosion are toxic to touch or breathe, so wear gloves and safety gear. Use a stiff wire brush to scrape off all the corrosion from the bolt, cable assembly and the battery terminal. A spray solvent will help loosen the corrosion. Dry the battery and apply a corrosion-resistant jelly or spray lubricant to the terminals. Reattach the battery, fastening the red cable first.
