There happens to be a couple of threads going regarding the cleaning of sails. Some say that you can use bleach some say no. Here is some information that I have collected on this subject which is open to comment and corrections. CLEANING - Dacron sails can be cleaned with mild neutral ph factor or Ivory soap. Use lukewarm or cool water (not hot). Sails can be soaked in a bath tub for very dirt material. This will help loosen up the dirt in the fabric. You can also spread them over a large clean area. Use a soft scrub brush for general cleaning. Scrub in line with the seams. After scrubbing/soaking rinse sail with plenty of warm water to remove ALL the soap or any other spot cleaners that may have been used. MILDEW/MOLD - Mildew will not affect the strength of the material. It is just unsightly and should be removed so it does not spread. To remove mildew, use a slightly stiff brush and soap to remove as much of the mildew as possible. The apply a solution of 1% bleach and cold water for a couple of hours, rinse throughly and reapply if necessary. Another method is to wash the stain in hot soapy water (with some bleach added). Rinse and let dry. Then moisten the stain with lemon juice and salt and let it dry in the sun. Rinse throughtly with fresh water. To prevent mold/mildew from re-appearing you can spray the sails with a disinfectant spray such as Lysol, this should stop the mildew growth. STAINS - Oil and grease stains can be removed with trichloroethylene or naphtha. If these type of stains are heavy you can also try brushing on a detergent dissolved in two pints of benzene or white spirits. This should be brushed on and left for 20 minutes and then washed out with warm water. Be sure that the area is well ventilated. Blood stains can be removed with mixture of a cup of ammonia to one half gallon of water. If stains are still present after the initial treatment, increase the strength of the mixture to 1 part ammonia to 10 parts water and allow to stand for another 20 minutes or so and rinse throughtly. Another method for blood stains is to use dry detergent and warm water. Make a mixture as a thick paste, let it stand for 15-30 minutes and then rinse. If the stain persists then try some more bleach solution *. There are other stains that you may need to deal with such as Rust. You can try a product called CLR (stands for Calcium Lime Rust). This stuff works great around the faucets and in the shower at home. I think it will be fine for a rust spot on a sail. Also a solution of 2% hydrochloric acid and warm water. Oxalic Acid for 15-30 minutes (use mfg recommendations for mixing). There are also the options of using Acetone rubbed on the spot with a clean cloth to remove Grease, Tar, Oil etc. Be sure to use a mild detergent and warm water to clean the spot after using ANY type of chemical solvents. These products may remove the stains, but they can also soften the various coatings on sailcloth. Remember whatever products that you decide to use, be sure that they are throughly rinsed from the the material and the sail is throughly dry before putting it back into storage. I find that hoisting the sails on the boat in a mild breeze for a period time is the best way to dry them out. If you always fold your sail the same way over the boom will also prolong it's life. If you have a system like the Dutchman you are going to have an easier time of keeping your main stacked and folded properly. NOTE: * Bleach solution should be about 1 part bleach and 10 parts water. DO NOT USE STRAIGHT BLEACH. PS: I would like to add that this is no replacement for having your sails professionally cleaned and reconditioned.