Davis Instruments - 790 FSR Fiberglass Stain Remover (16 oz.)

Stain remover works with no rubbing required.
Unique gel formula chemically removes stains with no rubbing required. Just brush on to the affected area, wait a few minutes, and viola—the stain is gone! Ideal for removing oil, rust, exhaust, waterline and transom stains. It's non-abrasive and is safe to use on white painted surfaces as well as on gel-coat.  
 
Key features 
Use where fiberglass stains crop up
Removes road soil from trailered boats 
Requires no sanding or compounding
Unique stain absorbing gel that removes oil, rust, exhaust, waterline and transom stains
Non-abrasive quality that is safe to use on white painted surfaces as well as on gel-coat