I tried the usual sail cleaning products on my self furler. Hopeless on green slime marks so I took the sail off and spread it out in my car wash bay at home so I had a hose handy just in case. I used a v strong bleach from the hardware and diluted it about 50%bleach and 50% water ( Isuppose you can scale up depending on the need) I did a test patch applying with a scrubbing brush and left it for 10 mins watching all the while. Then scrubbed again and hosed off, It worked and seems not to have affected the sail. However, if you use a strong hard brush avoid rubbing the seams on the sail as they can come undone. I had this happen in 1 section but used scissors to cut off the hanging thread. Some sail makers have a cleaning service where they dip the sail in some acid solution, my sister did this but her sail came back yellowish, altho it faded over time. The cost was much more than the bottle of strong bleach & elbow grease. Drying the sail was a bit of a problem ie finding a large enough area to hang it out. Also make sure you hose off thoroughly
