I have tried several products but can't remove grime from the underside of my awning. looks like mildew. the awning was in closed position for 3+ months and was not cleaned after last trip (a lesson ...
With a ladder, I start at one end of awning and work my way across spraying and wiping. Spray and wipe both sides of awning. The side facing the sky and the side facing the ground.
Let out about 2 feet of awning at a time, this way you can reach both sides as your working your way across.