Hollow plastic rats or frogs are great lures, but sometimes they take on water and become sinking lures instead of topwaters. well take it from me that very frustrating a sure cure is to get some foam rubber and cut it in to small peices. place your rat or frog on it's back, get a pair of tweezers or what i prefer forceps. ( for this next step rubber gloves are optional) now get a peice of foam and gently incert into the bottom of the victim. depending on the body of the lure you might shove a couple more peices inside the cavity. the form will float even when saturated with water. and the extra weight will add better casting distance, you can also inject your favorite scent.