What's the trick to keep your battery terminals from becoming corroded? Why do battery terminals beome corroded? Battery terminals corrode because of an oxidative process. To keep your battery terminals from corroding and causing electrical problems with your car or truck, clean the battery posts until they shine and then apply a product, such as petroleum jelly, on the terminals to keep the battery terminals from corroding in the future. Always use extreme care when working around batteries. Battery acid may splash on your skin or eyes. Eye and skin protection can't be stressed enough.