FSR (Fiberglass Stain Remover) is a unique stain absorbing gel that is ideal for removing oil, rust, exhaust, waterline and transom stains. Works like magic to clean up fiberglass stains! Can be use anywhere fiberglass stains may crop up. Ideal for shower stalls, furniture, removing road soil from trailered boats and recreational vehicles. Results within minutes! Simply apply with a brush, sponge or cloth. Wait a few minutes and then wipe off or rinse.