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. DIRECTIONS: Shake well. Apply using sponge or sprayer. Use of rubber gloves is recommended. Allow to remain on surface for 2 minutes then rinse with fresh water. Severely stained or dirty surfaces may require second application. For best results, use when temperature is over 50DegreeF. To shine and protect newly cleaned hull, apply any of Star brite"s Marine Polishes.