There is a long article and much more information on this at: http://extension.missouri.edu/publications/DisplayPub.aspx?P=GH5928
"Clothing and household fabrics
Remove mildew spots as soon as you discover them. Do not give the mold growth a chance to weaken or rot the material. Brush off any surface growth outdoors to prevent scattering the mildew spores in the house. Sun and air fabrics thoroughly. If any mildew spots remain, treat washable articles as described below. Dry clean nonwashable articles.
Wash mildew-stained articles at once with soap or detergent and water. Rinse well and dry in the sun. If any stain remains, use lemon juice and salt or another bleach. If you use a bleach, be sure to test colored fabrics for colorfastness."
at 4:01 PM on Jul. 21, 2009