Just found a super easy way to take the black streaks off

keep those magic erasers..they work great on the undersides of the awning, and it looks brand new when you are done. For the black streaks..my RV Dealer uses and swears by Soft Scrub with bleach. He said there's lots of expensive products that work, but soft scrub works just as well, and is cheaper than the rest..so that's what they use on all of the campers there.