Things You'll Need
Mild dish soap
It is perched so high above your head that you are unlikely to assess its condition on a regular basis. But one look outside a second-story window often confirms that your gazebo canopy canvas could use a good cleaning. Since canopies are exposed to wind, rain, tree sap, the sun and those winged creatures that are known to drop "missiles" along their path, canopies generally last only a few seasons. In the interim, you can keep yours in good shape – and perhaps extend its longevity – by keeping the debilitating effects of the outdoors at bay.
Remove surface dust and debris from the canopy with a soft-bristled brush. Follow up by hosing down the canopy with cool water.
Mix a sudsy solution of mild dish soap and warm water in a bucket. Err on the side of adding more soap than you think you need; it probably won't go to waste.
Wash the canopy from the top-most portion down with a sponge. Use the soft-bristled brush to scrub stubborn stains. Replenish the soapy water once the suds begin to dissipate and the water turns dark and dirty. If the canopy is too high to clean from the ground, and cannot be removed from its frame, use a stepladder and long-handled brush to reach the top.
Rinse off the soapy residue with cool water. Allow the canopy to dry in the sun.
Remove mold or mildew from the canvas by mixing a 50-50 solution of water and rubbing alcohol. Dip a rag into the solution and clean the canvas. Then hose off the solution with cool water.