The following Sail Cleaning advice comes from a respected boatwright, but seem a little "harsh" (to me).
Will anyone offer an informed opinion?
Witch''s Brew for sail cleaningfrom “Anzam Yacht Refurbishing” http://www.anzam.com/index_001.htm
To a bucket of water (2gal. or so +/-) add:
1 cup of boat soap
1/4 cup of TSP powder (Tri-sodiumphosfate)
1/4 cup of Oxalic Acid powder.
Apply solution, scrub with very soft brush, rinse with fresh water, apply solution, scrub again, rinse, rinse, rinse, rinse and let sun dry.
If possible, suspend the sail in sunlight. This works better than laying it on grass etc.
The boat soap makes bubbles and suspends the dirt for rinsing, the TSP gets the oil and dirt out, the Oxalic removes the rust stains.
If any of the "rust" stains are really stubborn, wet them with the above solution and work some additional Oxalic Acid powder into the area to make a paste... Leave it for a couple of minutes and rinse off while scrubbing with the **soft** brush.
If you can''t find Oxalic Powder (normally stocked at most hardware stores), use household "Deck Cleaner" crystals. This is not a boat deck cleaner, but wooden house decks (patio).