I guess I get to toot my horn once again! Mr. Clean Magic Eraser. If you can find the Mr. Clean Magic Eraser in the floor mop broom configuration, it works wonderful. If not, the little white sponges work fabulous, just take a bit more work.
When using Mr. Clean Magic Eraser on your awning, make the eraser wet, almost dripping. Wipe (do not scrub) a small area, about 2 feet x 2 feet. Follow up with a dry cloth or towel. If there are still spots, wipe a second time, or make it more wet. Black melts off. Move to the next 2x2 foot section and repeat until you've covered the entire awning.
Now! Do not rinse it! Just wipe it dry. The chemical which remain from the eraser will prevent black from returning. It will not stop bugs from getting rolled up into the awning, but a slight touch up, a quick wipe with the eraser to remove the bugs is all you have to do. Black will not return for a year! If you do it in the Fall, the awning fabric will not turn black over the winter all rolled up.
Yes, it takes just a little work to do it. But the pay-off is well worth it.
Remember, do not scrub. Too much "scrubbing" and you could rub a thin spot in the awning. Simple wiping lightly will remove the gunk and not hurt the awning.
Mr. Clean can be used on everything in your camper, including the outside skin. Just remember, wipe ... do not scrub and make it wet but not dripping and followup with a dry cloth.