FSR Davis Fiberglass Stain Remover , 2 Liters - 792FSR (Fiberglass Stain Remover) is a unique stain absorbing gel that is ideal for removing oil, rust, exhaust, waterline and transom stains. It can also be used anywhere else fiberglass stains may crop up - shower stalls, furniture, etc. Use for removing road soil from trailered boats and recreation..