TotalBoat Krypton and TotalBoat AlumiPaint AF can be applied over properly prepared previous antifouling paints that contain tin. At a minimum, the tin copolymer antifouling paints must be thoroughly sanded and wiped clean with a lint-free rag. Heavy sanding or removal of the previous antifouling paints that contain tin are also viable options before applying Krypton or AlumiPaint AF.