3M Marine Mildew Stain Remover cleans and eliminates mildew from most marine surfaces. Our easy-to-spray powerful formula cuts into virtually any layer of mildew that grows on a boat. After applying, simply wipe with a cloth to reveal a fresh, clean surface free of unsightly mildew and mold. Once the surface is clean, follow up with 3M Marine Mildew Block to help prevent it from recurring.