Fabric awnings can become dirty and even mildewy from being out in the weather. Cleaning them without damaging the fabric or colors can be a challenge. Besides having a water hose and scrub brush, you need to choose a cleaning agent that won't bleach out the color or be too strong for the fabric causing it to break down. Many awnings are treated with a waterproofing coat as well so you will want to refresh that after cleaning.
Fabric Laundry Detergent
Mixing your favorite laundry detergent in a bucket of hot water and scrubbing your awning is a safe way to clean the fabric without damaging it.
Vinegar will remove dirt and mildew while killing mold spores and other bacteria that may be on the awning. Additionally, vinegar is safe for the fabric.
Dish Washing Detergent
A gentle dish washing detergent such as Palmolive or Dawn is a safe cleaning agent for your fabric awning.
Basic upholstery cleaner that you can find in any store that sells cleaning products is good to use on a fabric awning.
Baking Soda Paste
Mix baking soda with a small amount of water to form a paste and scrub your awning with it. Baking soda cleans and refreshes without damaging the fabric, and rinses away clean.