Here's an environmentaly safe product
A friend of mine told me to use baking soda. Especially when you are in the slip. The baking soda is a gentle abrasive. I just dump a bucket of water on the area that I intend to clean, then sprinle some Baking soda, be generous, it's cheap. Use a sponge or soft bristle brush, then rinse with a couple of buckets of water. Move on to the next area. The non-skid will be extra grippy,(I just made that word up)

The gelcoat of the cleaned area will have a lot of the haze from UV rays cleaned away, and makes older boats look newer!