Penatrate and eliminate tough stains on vertical and sloped surfaces. The gel formula of our Fiberglass Stain Remover allows the cleaning agents to stick” to and penetrate stains to lift them from the hulls and decks of fiberglass boats. The thicker gel makes this stain remover ideal for removing yellowing, rust, waterline, leaf and fish blood stains on sloped and vertical surfaces. West Marine Fiberglass Stain Remover is the solution to challenging stains on sloped or vertical fiberglass and painted surfaces. Key Features Gel formula sticks to and eliminates stains Great for sloped and vertical surfaces Effectively removes rust, leaf, fish blood stains and more Compatible with fiberglass and painted surfaces Removes yellowing 22 oz.