[PerryC]

Sebastes,
Like Seaslug said, you can remove scratches in a rotomolded kayak with a heat gun. But, you have to be very careful while doing so. If there is a texture to the kayak like tiny dimples in the area you heat, you may smooth them out which would look like a blem, or worse.

For removing paint, you may want to contact Kiwi Kayaks and see what they say about a remover. I'm sure pressure washing would be fine, but I'm not sure how much paint it would take off for you. Who else might know is a automotive body shop which paints flexible parts. They might know of a remover which is gentle on the surface under the paint. Good Luck and let us know how it turns out. TC&TL,
Perry