If you take a cotton t-shirt and put it in a bucket of bleach water and let it sit over night, remove the shirt the next morning. Rinse it out, dry it, then put it on... you'll never use bleach again on your awning. The bleach will deteriorate anything it touches. The stronger the bleach the more harsh it is, but if repeated over and over, each "tiny" amount will deteriorate a "tiny" amount. Over time, just like that t-shirt, an awning will begin to shred. I've ruined too many things with bleach ... including a dump valve on a previous camper when I used bleach water to clean the black tank and left it in there too long without rinsing completely. I don't use bleach there any more either.