Cleaning a composite kayak

I just rinsed off my kayak and noticed that parts of the white hull seem a bit more discolored than I remembered. It’s got some dull yellowish staining. Is it necessary to remove this and if so how? Thanks.

I use this stuff called FSR that’s a blue gel that removes fiberglass stains, hence the name Fiberglass Stain Remover. There’s a million things more or less just like it I would guess.

Warm water and Dawn have worked on the gunk accumulated on my hull. But that was mostly fresh water pollen stains in the spring.

I use it on both thermoform and kevlar boats.

Great, thank you both!

I had the same problem with both my composite boats.
Same dull yellowish staining at the end the season.
Used starbrite Hull cleaner and back to nice white gelcoat

Like John I use Starbright on fiberglass boats. I also use a buffer.