Black Spots on underside of Awning - How to Remove?

I was told that one of the causes of the black spots on the inside of the awning is outside cooking. The vapors from a grill or outside stove during cooking will deposit on the awning. You cannot see them but the grease is a point from which mold can grow.

I use the same methods other have mentioned. I personally use a awning cleaner that I spray on then roll up the awning wet for 15 minutes. I then open the awning and rinse the residue off.