I went on a weekend trip and left my boat in the water all weekend! I keep it clean but I cant get the yellow splotches off now. Its a white hull so I see it very well. I dont want it to look like one that stays in the water all the time. Got any helpful ideas?

3M marine polish and wax, wally world or academy.
will clean it real good and leave a good wax on it without much effort.

Hull Cleaner or Kaboom

Davis FSR (Fiberglass Stain Remover) Wipe it on, wash it off. No scrubbing. Best stuff I have ever used to get stains off of white fiberglass.

Great! Thanks alot! I'm gonna go try it now!

I had the same deal on my boat.Went to Wal-Mart bought Attwoods Hull cleaner.Wipe it on with a sponge and it seems to just melt away the stains also make sure u wear gloves it burns if you get it in a cut.

Almost forgot try the Magic Eraser.

I used some stuff called Toon-Brite to get the east texas scumline off a white hull I had. Worked greeat. Afterwards, wax that hull and the stains hardly have a chance anymore. It worked well for me but wax don't last forever. Fiberglass is not slick, it has pores for the stuff to get hold of and hang tight. Fill that with a good waxing and you're good to go.

If you use any of the acid based cleaners, be sure to rinse the trailer very thoroughly. The cleaners are very hard on the fabric on the trailer bumpers. I know from experience.

Have you tried a spray bottle with 1/2 water + 1/2 Vinegar? Works on everything I get on my boat.

I use this all the time for water spots. It works great