I have to thank my dad for coming across these bargains and to all the helpful people on this forum who gave the info needed so I could restore this beauty. I still have to sand the epoxy hull repairs and polish/finish the hull. It seems supers are rare, so message me if you need help with something or whatever.
That is a big reason why the boat was free! He figured it was rotten and needed to be replaced. With the wisdom found here, that 42 yr old sail has fewer issues than my 41yr old body! Everything was stored in a garage though.
Step 1 was to really wet the sail spray wd40 on the really nasty spots, and let soak for a few minutes, scrub w Castile soap, rinse, clean w simple green, rinse thoroughly.
Step 2 was to soak in borax bath overnight, turning every hour (or you could hold it under water with a rock) and gently scrub and rinse both sides.
Most people say to avoid wd40 and other harsh chemicals, but I had nothing to lose, so it was worth the shot. I think the Borax soak caused the Sunfish image to come out of the sail, but it was pretty faded beforehand.