Star Brite® 81732 Instant Hull Cleaner, 32 OzCleans scum lines and stains on boat hulls easily and effortlessly. Instant Hull Cleaner is formulated to begin working on contact to remove unsightly waterline stains. It is also very effective at removing rust stains or leaf stains from fiberglass or painted surfaces. It will not harm the surface being cleaned and is an ideal preparation for polishing the hull. Size: 32 Oz Does not contain harmful acids, safe and easy to use Quickly removes stains