Further info - Specific cloth needs.
Don't let any solvents (such as diesel fuel or cleaning agents) get on them, because these will dissolve the glue and cause separation.
Dacron. If mildew occurs...
Treat mildew at the earliest possible moment. If you do not, it can spread quickly. There is an excellent chance of getting mildew stains off when they are new, relatively small, and close to the surface. There is little chance once they have spread and set into the fibres.
Isolate mildew-infected sails, covers, and so forth, from clean sails.
The quickest and surest way to spread mildew is to rub an existing growth against a receptive surface.
The single most popular mildew killer and remover is simple household bleach. This is also known as sodium hypochlorite, sold in the U.S. in 5.25% solution with water. This is potentially nasty stuff and manufacturers recommend diluting it quite a bit further before using. Tilex® and other "mildew removers" are mainly sodium hypochlorite in solutions of about 3%, which is still a pretty healthy dosage.
DO NOT use BLEACH (Sodium Hypochlorite) on KEVLAR® or NYLON, EVER, UNDER ANY CIRCUMSTANCES!!!
This is one of the few known, proven solvents for these fibres. Of course, this means you should not clean KEVLAR® and nylon with Tilex® or other commercial mildew cleaners that contain sodium hypochlorite.
DO NOT EVER MIX BLEACH AND AMMONIA and stand around breathing the air. The result is phosgene gas which killed and disabled thousands in the First World War. This little home science experiment continues to kill and cripple people to this day.
For particularly stubborn, deep set stains, surface cleaning will not work. It is necessary to immerse the stain in a fungicide for 12 hours or more, to allow it to get in to where the stain is. It is not necessary to use a particularly high concentration, only to get the fungicide where the stain is. No amount of vigorous surface scrubbing will do what a good soak will do.
After washing with bleach, always rinse thoroughly with plenty of fresh water. Bleach that is not removed can cause long-term structural damage that is more harmful than the cosmetic damage caused by the mildew.
If the mildew stain does not come out after one good wash with the proper equipment and chemicals, give up. Experience shows that further washings/scourings/ treatments remove very little additional stain and
cause a lot of other damage.