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 ...
I've always, except on one occasion, used awning cleaner specifically designed for the purpose, and with great results. The one time I tried that "bleach / water mix and roll up the awning" trick it irreparably damaged the awning vinyl which I then had to replace ... and that which dripped off the awning also destroyed the shirt I was wearing at the time. :M