Position the umbrella in a shady location to prevent soap from drying on the canopy during cleaning. Open the umbrella fully.
Pour a small amount of mild detergent into a bucket and fill with cool water. Dip a soft-bristle scrubbing brush into the water and gently scrub the surface of the canopy, using a ladder to reach as necessary.
Continue scrubbing the canopy until the entire surface has been cleaned. Discard the detergent water and mix a new batch as needed if the water becomes excessively soiled.
Turn the nozzle of the hose to the "Spray" setting and rinse the canopy thoroughly until the water runs clear. Allow the canopy to dry completely before closing the umbrella.