clean boat very good, if white, would recomend bleaching after washing and good fresh water washdown after. PG covers the surface and soaks into the surface locking dirt/stains in. when dry, apply with clean lint free rag/old 't'shirt. takes several coats, as much as 6-10 depending on gelcoat surface, to get final shine. touch up as needed, no need to strip before tuch up. amonia will strip away PG is desired. once or twice a year wipe down here in fla sun. most all like it here.
It comes in a kit, with cleaners & applicators, although you can use lint free rags as well. The cleaner/stripper is very good & as previous post, the PG does "lock in" any dirt, hairs etc that fall on it during drying. Having said that, each coat dries in minutes, so it is not too much trouble to get a nice finish. IT WILL NOT HIDE any discolouration in the gelcoat, but it sure does give a beautiful shine, with excellent lifespan. Did some of my coachroof last summer & still looks immaculate.
Best of luck with it, all you need is elbow grease & a fine dry day.