I've been through that and the acrylic fabric is a $%&*# to clean once the grime gets down in the pores. If it is tree sap, grease, or just the black detritus of leaves and bark from parking under trees, I'm afraid there is not a lot of hope. None of the so-called "awning cleaners" I have tried did much of anything for it and usually less effective than regular household detergents.
Here's one trick for deep-set grime: wash it down well with your favorite fabric cleaner, e.g. a liquid laundry detergent or general purpose detergent. Rinse copiously cause the loosened dirt goes right back in the pores otherwise. Then make a STRONG solution of OxyClean detergent and wet is down thoroughly, then roll up the awning and let it sit for 45-60 minutes. This keeps the solution wet and in contact with both sides and all parts of the awning. Then unroll and re-wash & rinse.
Use isopropyl alcohol to remove pine tree sap - it dissolves the stuff. But it is still hard to get out the part that has seeped into the fabric pores. Nearly impossible to get it all out.
The fabric itself is strong and won't be harmed bu detergents or scrubbing, but the fabric may leak in spots after using strong cleaners or scrubbing in one spot - it relies on a waterproofing substance in the pores like an old canvas tent did. You can re-waterproof, though, and it isn't too hard. Waterproofing that is safe for acrylics is available in many outdoor stores - read the labels. Spray cans are the easiest to use, especially if you just need to touch up a spot.