Hi Donna, In my experience, the best caulk for wet applications is a non-waterbased silicone caulk such as R.T.V. This is a rubber based caulk that cures when exposed to air. It is 99.9 % effective, however, it smells like vinegar when curing and cannot be painted over. (R.T.V stands for "room temperature vulcanization") The old surface should be clean prior to application of the new silicone caulk. By the way, clear caulk looks pretty nice in most applications, but silicone caulk is available in several colors such as white, alumninum, bronze, etc. If you have any questions, drop me a follow up.