If you have a Sunbrella bimini/dodger, bombed by the birds, this is what works:
Spread the canvas out on a driveway or other flat outdoor surface; hose off as much of the solid matter as you can get. Fill a bathtub about 5" deep with cool-warm water and add mfr's recommended amount of Oxy-Clean. Be sure Oxy-Clean is fully dissolved. Water should feel soapy and slick to the touch. Put the canvas in the tub; let it soak a good half hour or so, occasionally agitating it by hand. (I put the canvas in a large trash bag for transport to the house; saves the need to clean up the drips later.) After soaking, remove the canvas back to the driveway (via plastic trash bag again); rinse thoroughly using garden hose and use a nylon pot scrubber, or the business side of a nylon backed sponge to address any stubborn stuff that remains. A little elbow grease should be all that is required; any remaining white stuff should come right off. Dry the canvas in the sun; it will look like new. Sunbrella recommends treating it with 303 High Tech Fabric Guard to restore any lost resistance to weather.
Spread the canvas out on a driveway or other flat outdoor surface; hose off as much of the solid matter as you can get. Fill a bathtub about 5" deep with cool-warm water and add mfr's recommended amount of Oxy-Clean. Be sure Oxy-Clean is fully dissolved. Water should feel soapy and slick to the touch. Put the canvas in the tub; let it soak a good half hour or so, occasionally agitating it by hand. (I put the canvas in a large trash bag for transport to the house; saves the need to clean up the drips later.) After soaking, remove the canvas back to the driveway (via plastic trash bag again); rinse thoroughly using garden hose and use a nylon pot scrubber, or the business side of a nylon backed sponge to address any stubborn stuff that remains. A little elbow grease should be all that is required; any remaining white stuff should come right off. Dry the canvas in the sun; it will look like new. Sunbrella recommends treating it with 303 High Tech Fabric Guard to restore any lost resistance to weather.