Starbrite Ultimate Fiberglass Stain Remover - Gel Formula Starbrites Ultimate Fiberglass Stain Remover is a gel formula sticks where applied for maximum cling time and cleaning power. Use this stain remover to get rid of the toughest stains including rust, dried fish blood, and leaf stains. Features Gel formula clings where applied for maximum cleaning power Removes yellowing and tough waterline stains Completely covers stains to penetrate and dissolve them Specifically formulated to remove the