FSR (Fiberglass Stain Remover) TEMPORARY OUT OF STOCK FSR 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. Its non-abrasive quality means that it's safe to use on white painted surfaces as well as on gel-coat. Just be sure to test a small area first to be sure FSR will not damage finish. Requires no sanding or compounding. Simply apply with a brush, sponge or cloth. Wait a few minutes and then wipe off or rinse. Sizes available, 16oz jar and for really big clean-up jobs the 67.8 fl oz (2 liter) bottle.