I would ask your dealer or call the customer service for your brand of awning.Sap is going to require some type of oil based solvent and I'd want to know the right stuff to use on it.
As for the cleaning here is how I have done it on my last few awnings.
Asumming you have a manual awning,on a calm day,,get yourself a helper ,,,pull it out all the way,,,don't extend the arms,,leave the angle braces hanging,,now with you on one leg and your helper on the other,,,,,pull the bottom pins from the brackets on the trailer just as you would if you were puttting them out while camping but insted of standing them up carefully let them go back under the trailer,,,this will let the awning lay flat against the side of the trailer so you can scrub on it.
I've done this with CareFree and A&E awnings,it's one thing I going to miss with the electric one on my new rig, but since you can stop an electric any place you want I just stop the place I want to clean as it comes out of the roller.
2010 298 RLS Eagle
99 Ford F-250
1 Toy Fox Teror
1 Tiny Chi Chi Wa that rules all of the above.