Old Gel coat
can be brought back. There's a Jelly type of solution that can be bought in the marine stores that works great on old Gel coat. I can't recall the name of it off hand but it's in a can or plastic container. Check out the West Marine site and click on to "Fiberglass cleaners" Under "Product Advise" click on to "Gel coat Shine Restoration." or "Gel coat Stain Removal." You'll find a lot of useful information on this subject.Joe