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 ...
Mixture of bleach and water wet the whole awning then roll it up for about a half hour. Open it up and scrub it clean. And don't feel bad it gets dirty when rolled up, water gets inside mine so I kind of gave up on keeping it looking brand new.