Remove boat from water and knock off large marine deposits. Allow marine deposits and stains to dry thoroughly. Stains and deposits found above the water line may be removed while boat is in water. Pour product into an open plastic container and apply to the dry surface of hull using a natural bristle brush. Keep the deposits and stains wet and foaming with the product. Foaming indicates the product is removing the deposits. Keep reapplying the product to maintain foaming action. After a few minutes of foaming action, most surfaces should be clean and ready for rinsing with water. If large amounts of marine deposits are present, several applications and some light scraping may be required.