If you spot corrosion (white build up around the terminal), you can remove it yourself by carefully following the easy steps listed here.
Step 1: Disconnect the battery - Disconnect the wires from the negative batter post. Do not disconnect the positive post first. By disconnecting the positive post first, you run the risk of electric shock or burns if your tools come in contact with the exposed post and the metal of the vehicle. Put the wires aside.
Step 2: Mix a cup of water with a teaspoon of baking soda - Either pour the mixture on the corrosion directly or wet an old rag with the mixture and wipe the corroded area with it. The baking soda will dissolve the corrosion quickly and allow you to remove it easily.
Step 3: Clean the terminals – Once corrosion is removed, clean the battery terminals with a wire brush or a toothbrush with baking soda mixture applied to it. Ensure that the posts are making a good connection.
Step 4: Reconnect the battery – Wipe off any excess moisture off the battery and terminals and reconnect the wires, starting with the positive terminal and then the negative.