Awnings are a less expensive way of shielding patios and motor homes from the sun. They are available in vinyl or fabric as standard or retractable covers. Awnings are susceptible to a growth of algae, mold and mildew, just like anything else exposed to the outside elements for a continuous amount of time. Washing with soap and water is usually not enough to completely remove the green stain of algae, so a concentrated solution such as hydrogen peroxide is necessary. Clean your fabric awning carefully to preserve its color and the weave.
Move plants away from your work area and use protective coverings on other items close to the awning, such as furniture and cars.
Mix one part hydrogen peroxide with six parts of water in a bucket. Pour some of the mixture into a spray bottle.
Spray the rest of the awning with the solution and let it sit for 30 minutes. Spray water on the awning to wash off the grime. Repeat this process if necessary.
Wash the awning. Working in small sections, scrub the awning with a soft brush and soapy water, then rinse. Let the awning dry.
Spray a solution of one part vinegar and one part water on the awning to protect it from growth of more algae. Let it dry.
Use a product such as Aqua-Tite to restore the waterproof finish of the awning.
Know your limitations. In some cases, it is best to have a professional do the job. "For heavier jobs or on hard-to reach awnings, the best step is to call a professional who will attack the problem with a pressurized water cleaner that flushes dirt and grime away", says Jeff Bredenberg in Clean It Fast, Clean It Right: The Ultimate Guide to Making Absolutely Everything You Own Sparkle & Shine.