FSR Fiberglass Stain Remover Gel - 12 oz Jar. Great for removing Rust, Oil, Exhaust and Waterline Stains. Stain absorbing and great for removing rust from Stainless Steel and deck or hull areas. Removes rust stains from sail cloth, clothing, fabrics and concrete. No sanding or compounding needed. Apply with cloth, sponge or brush . Allow to sit for several minutes. Then wipe off or remove with water.