It's not uncommon for a car battery's terminals and/or the connectors to develop corrosion. This usually doesn't happen overnight. Rather, it takes months or even years of exposure to moisture before any noticeable amount of corrosion develops. Once it develops, however, you may experience problems when attempting to start your car. Corrosion prevents the flow of electricity from the battery to your car's electrical system, which can prevent the car from starting. Thankfully, you can clean corroded battery terminals in just a few easy steps.
Disconnect the Battery
Prior to cleaning the terminals, you should first connect the battery. Doing so will give you more room to work with while also protecting against accidental shock. Depending on the make and model vehicle, you should be able to disconnect the battery by removing a loosening a nut on the positive and negative terminals. Just remember to loosen the negative terminal first, followed by the positive terminal second.
Baking Soda and Water
There are dozens of ways to clean corroded battery terminals, though one of the most effective (and cheapest) is to use baking soda and water. Moisture alone is usually enough to cause battery terminals to rust. The oxygen within moisture causes the metal terminals to "oxidize," beginning the formation of rust and corrosion. However, excessive corrosion on battery terminals is usually a sign of spilled acid, for which baking soda is highly effective at cleaning.
You see, baking soda works to neutralize spilled battery acid. From the moment it makes contact, baking soda will begin to sizzle and neutralize the acid. This not only makes cleaning the corrosion easier, but it also makes it safer. So, prepare a solution of 1/2 cup baking soda and 1/2 cup water and stir until it turns into a paste-like consistency.
Cleaning the Terminals
After preparing the baking soda and water solution, you can begin cleaning the battery terminals. It's recommended that you use a stiff-bristle brush for this purpose. Either apply the baking soda solution directly to the terminals or apply it to your brush. You can then scrub the terminals until the corrosion comes off. Continue doing this until the battery terminals are shiny, after which you can dry any remaining liquid and then reconnect the battery.
Of course, you should get into the habit of inspecting your battery terminals on a regular basis. As long as you keep them clean, corrosion shouldn't be a problem.