I've been fighting dirt/mildew on my SOB awning. Saw a post on another forum from a reliable poster promoting a product called "LA's Totally Awesome Cleaner" that he had gotten from Home Despot(
). I picked up a 20 oz. bottle at a Dollar General store. After using, my awning now looks almost brand new.
The I started with the 20 oz. spray bottle was $1. It did such a good job, I went back and bought the 1/2 gallon for $3.
My method - spray the awning with water to get wet. Spray the Awesome on full strength and wipe wtih a wet micro fiber cloth. Rinse well.
FWIW the bottle claims: No Acid, No Ammonia, No Bleach. Safe for septic tanks. Contains no phosphorous.