I use
Oxyclean and Crud Cutter. I use a pressure sprayer, soak sails well, and with a fresh sponge encourage any tough stains to leave. Then simply rinse with the hose. I do this while the sails are hung on my deck railing. I find Oxyclean works especially well. But repeat wash and rinse is necessary otherwise you end up with bright sails but a darker stitching. For some reason it is hard for me to get the stitching as white as the sails but that will never be reason to pay to have them done professionally. Take care of your sails and cleaning will not be so much of a chore or concern.
