don't think they're dacron, cleaned my hobie cat sails last spring with a scoop of OXI-clean in a clean garbage can. let 'em soak for a few days then layed them on a big tarp in the drive way and scrubbed with a soft brush, rinsed with a hose and back in the bucket with more OXI-clean. several days and another rinse later raised them on the boat to dry. made 'em look pretty again.
the " better things " in life , aren't "the things" . . .