From the bloggers at Love Your RV.
Our large 21 foot Dometic 9100 RV power awning is made out of vinyl and has held up very well after 4 years of full-time RVing. I generally clean it every few months by following the procedure outlined in the owner’s manual.
The manual advises using a mixture of ¼ cup bleach, ¼ cup dishwashing liquid added to 5 gallons of water. It then states to spray this solution liberally all over the top of the awning and roll it back up. Wait about 5 minutes, unroll the awning and hose it off well with fresh water.
I have my own little method of doing this. I use a 1.5-gallon manual pump garden sprayer filled with water and add about 1/8th cup of bleach and 1/8th cup of Dawn dish soap.
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