2x on the Mr. Clean Magic eraser with a bit of elbow grease. Actually, we found the Mr. Clean Magic Eraser on a mop handle, and it's so easy to reach the underside of the awning.
Directions for Mr. Clean Magic Eraser for success: Make the sponge wet, but not completely dripping. Simply wipe it over a small area, about 2 feet x 2 feet. Take a dry towel and wipe if off. Move over 2 more feet and do the same. If there is still some black left, wipe it again and dry off with the towel. DO NOT SCRUB, just a simple wipe.
Mr. Clean Magic Eraser also has the right combination of chemicals that prevents mold and black from coming back. I do my awning, usually during our first camping trip of the season, and then just a simple spot touch up the remainder of the summer to get squashed bug and bug poo off. There again, simple wipe and dry, and done!
Actually, I opened my awning yesterday, (temps got up to about 50 degrees here), and there is no black anywhere. I haven't touched it all winter.
Roof:
I am old school here and bit more protective and a LOT more skeptical. I use only RV rubber roof cleaner sold at WalMart or my local RV dealership, and ALWAYS follow up with the RV roof conditioner. Pour a little on, use a window squeegee to spread it around and let it dry. Keeps the rubber membrane nice and slick! (careful walking on it after applying it will be slick).
That's how I do it.