After you clean it up and put it back together, smear a bit of plain ol' petroleum jelly from the medicine cabinet or other grease over the terminals as a preventative measure. As someone else noted, if you'd like to spend a buck or two, you can buy (1) felt washers that go onto the terminals, under the clamps, (2) stuff in a tube that is basically petroluem jelly with a bit of other stuff that might make it work better than petorleum jelly alone, or (3) some stuff is a spay can you can spay onto the terminals that dries. The last spray on stuff is usually colored red, purple, or some other color, simply to aid in insuring you have gotten complete coverage when you spray it on the terminals.