How to Clean Corrosion Off Car Battery Terminals

Properly maintain and clean your battery terminals often.

Corrosion on your car's battery terminals can prevent your car from starting up. The corrosion is usually caused by a buildup of sulfuric acid on the terminals, and it often looks like a crusty, white residue. When the battery terminals (or posts) have this kind of buildup on them, your car is not receiving all the power generated by the battery. You can easily clean off the corrosion with a simple mixture, then protect the terminals to keep them cleaner longer.

Things You'll Need

• Car owner's manual
• Keys
• Wenches or pliers
• Baking soda
• Water
• Cup
• Toothbrush OR
• Terminal cleaner tool
• Petroleum jelly

Instructions

1. Turn off your car's engine and remove the key from the ignition.

2. Read your car's owner's manual to check what will be effected when you disconnect the battery cables from your car battery, before you disconnect the cables. Besides general loss of power to radios and clocks, many newer vehicles have electronic features that can be disrupted if a proper procedure is ignored before power is severed. Your car's owner's manual should address those features, telling you how to proceed properly when you are going to disconnect your battery cables.

3. Use the proper size wrench or a pair of pliers to loosen the nut on the battery cable clamps. Always loosen and remove the negative clamp and cable first, then the positive clamp and cable.

4. Mix one tablespoon of baking soda in one cup of water, until it is dissolved. Pour some of the baking soda solution on the corrosion on your car battery terminals. You may see it bubble and foam--that means the baking soda mixture is breaking up, dissolving and neutralizing the acid corrosion.

5. Use a toothbrush or battery terminal cleaner tool to further loosen and scrub off the corrosion from the battery terminals and the inside of the terminal clamps. Stubborn corrosion may take quite a bit of scrubbing and another application of the baking soda mixture, but the corrosion will come off.

6. Using water, rinse the baking soda mixture completely off the terminals and battery. Make sure you use lots of water to completely remove all the baking soda mix and old corrosion.

7. Allow the battery terminals and battery clamps to dry completely before you reconnect the clamps to the battery terminals. You can coat the terminals, after they are dry, with a thin layer of petroleum jelly before reconnection, to help eliminate corrosion from building up quickly. Make sure you reconnect the positive battery cable first, then reconnect the negative cable.

Tips & Warnings

• The baking soda solution is only for external use on your battery. Make sure you do not get any in the inside of your battery.

References

• North Dakota State University: Battery Basics
• Edmunds: A Shocking Expose: Your Car's Battery
• Auto Jab: How to Care for Your Car Battery

Resources

• Second Chance Garage: How to Clean Battery Terminals