I have a customer with an RV with oxidized gelcoat. He says that the tap water has iron in it and tends to leave brown marks. He tried Castrol Superclean (this is glycol ether, detergent and caustic in water) and it "drove the stains deep" so that they could not be removed. He tried over 10 different products, including CLR, Simle green, Mwguirs etc. The only thing that did anyrhing was to remove some of the gelcoat with heavy duty rubbing compound. SEA GLOW did not work either, although we make no specific claims about rust stains. I once came accross a rest remover called "Majica" that worked well on some patio concrete that had rust stains, but cannot find the product now. Here in Hawaii we have a product called "Misty" that a friend of mine tried on gelcoat and it worked. well. While I have had luch with our SEA GLOW on white gelcoat, the rust was not very deep and only in the chalky pores. I am asking for feedback on this, not only for this customer but becuase I have a bad rus stain from a stress crack around a coach roff bolt (can be seen on www.IslandGirlProducts.com/nonskidpage.html). I tried naval jelly and it worked a bit but bleached some of the beige non-skid. Any suggestions? I will try oxalic acid-based stain remover and recommended that to the customer. Thanks, Jim Willis