There are some stains that nothing will get out, and if bleach doesn't do it, not much will. The trick is to leave on there for a while. The (my version) “formula” is about a cup of bleach per gallon of water, a couple of squirts of soap of your choice. Mix all this in a yard sprayer and spray the top of the awning liberally with the mixture. Roll the awning up and let it stay that way for a while. Unroll it and most of it will be clean. You may need to repeat and/or use a medium brush on a stick for the stubborn stuff.
