I had pretty good results using KrudKutter and an automotive carwas brush with a hose attachment so that water ran through the brush. My clear coat is not in particularly good shape though and I can not say absolutely whether or not it did anything to the clear coat.
I have recently seen ads on TV and shelves full of a moss/mold removal product at Lowes that supposedly is delicate on the underlying material and the environment. The product is called 30 Seconds. Check it out at the following Lowes website link.
Concentrate (1 Gallon)
Has anyone used this product? I need to clean my AS off again and might give this stuff a try. If I do I will report back.