I was using Simple Green. I had bought a bottle of black streak cleaner and once, after a weekend under some very dirty trees, couldn't get the roof clean with SG and sprayed some of the black streak cleaner. That took the dirt off quick and easy.

I had stopped at a local RV service place for some parts and was going to buy more of the cleaner, but they talked me into a concentrate that they use for everything from degreasing to black streaks. Great stuff! I've started using it in the house and shop in place of most every other cleaner we had.

Unfortunately, they buy it from a local distributor, who just labels it as RV Cleaner. But, if you check with your local repair places, they just might have something similar. Note, I said repair, not sales. The place I go to doesn't sell RVs and doesn't have much in the way of a store, but does have a parts counter. They sell what they actually use and what recommend what works for them.

John

I usually opt for borax and a brush.  I happen to have a power brush that I like.