Just thought i'd let everyone know Starbrite Hull Cleaner worked a treat getting some iron stains off the gel coat of my hull - which had baked on due to heading south with work for a fortnight after wash down. Don't normally plug products, however, was dubious it would work, and it came good! Left it on for ~5 minutes (wouldnt leave any longer - uses oxalic acid) - did three rounds of this (washing off between). Then proceeded to wash/wax and re-polish the gel coat....... Wont be making that error again!