I like the following three 3M products. I've used them all on various old boats. They're the ones used by the pros in the two boatyards I've worked in.

3M™ Marine Fiberglass Restorer and Wax 09005 - about $10-$15 for a small bottle that's big enough to do a Potter. It'll remove pretty heavy oxidation and wax in one step with an orbital polisher. For routine maintenance too, as it doesn't remove an inordinate amount of gelcoat. 3M says: "Designed to remove HEAVY oxidation, chalking, fading, minor scratches, rust and exhaust stains; plus provide protection on fiberglass/gelcoat."

3M™ Marine Super Duty Rubbing Compound 09004 -- if the Fiberglass Restorer and Wax doesn't do the job, this stuff will. Use an orbital buffer for the big surfaces and a hand cloth in the nooks and crannies. But keep in mind that it's aggressive -- it'll remove almost as much gelcoat as wet sanding (but with much less work). 3M says: "Suggested for heavy, aggressive compounding of oxidized gelcoat and marine paint. Clings to paint and gelcoated surfaces - remains wet on the job with little or no mess. Buffs to high gloss with minimum of swirl marks. Can be used by hand or machine."

3M™ Marine Finesse-It™ II Finishing Material. If you really want a gorgeous finish, follow up the heavy duty compounds with Finesse. Or use it annually for light buffing. This stuff does a beautiful job of making gelcoat look new.

Fair winds, Judy B