Cleaning your car battery terminals is important in maintaining your car. It is a simple process that you can do at home with a few supplies. You will need: baking soda, water, a toothbrush, and gloves. First, disconnect the positive terminal of your battery and then the negative terminal. Next, mix a solution of baking soda and water. Rub the terminals with the solution using the toothbrush. Finally, rinse the terminals with clean water and reconnect the terminals.