A mild bleach in solution with any form of soap will be fine to scrub the sails with - but be sure to rinse it thoroughly with fresh water
after. Getting down on youer knees with a scrubbing brush will also help.
Not sure what the equivilent is in the US but in Europe
we find either Ciff or Jiff (same cream type kitchen cleansers over this side) do a good job in removing marks from glass before then polishing with a non slip product - and a fraction of the cost of marine
Finally if you've got any rust marks on the hull
or indeed any stainless parts
, a mix of oxalic acid crystals (you can get from a swimming pool shop) with water
(4 table spoons per gallon) and left on for fifteen minutes should see it all dissappear. Again - wear gloves and eye protection and rinse well with fresh water after.