THE WORKS
Jim,There is a product out there called THE WORKS. I buy it in a 16oz bottle for $1 at the local Dollar General store. It's found where 409, Simple Green and similar household cleaners are. It's a mild acid and I have used it on 3 boats I have owned. H23, Precision 21, and now the H23.5. Excellent results with each boat.Squirt the stained/dirty area with THE WORKS, after it sits for a minute or so, scrub it with a still (plastic) brush. Let it sit (and more if needed) for a few minutes and scrub more. Rinse it off. Reapply if needed.Around here, a boat will get the "ICW mustache" the brown stain at the waterline. THE WORKS takes it right off!I'm serious, this stuff is great and cheap. A 'cleaning lady' told me about it. she uses it on fiberglass showers and tubs. She buys cases at a time.It works for me,Mike