Any kind of detergent, chlorine bleach, ammonia, borax, or oxygen cleaner binds the copper blue in the water to fabric in the laundry. If you fill the tub with water and detergent and agitate to mix before adding the laundry, things will get a uniform bluish cast, rather than dark areas where the water runs onto concentrated detergent on the laundry. The loger you wash a load, the more copper is laid into the fabric. Even the products (white vinegar, Calgon) suggested by a university extention site did not work. THe ONLY thing that did work was an old bottle of The Works (not the one put out by Clorox) but by HomeCare Labs. THe active ingredient was phosphoric acid. THe formulation has been changed now and it doesn't work as well. THe old formula completely removed the blue from a colored linen/rayon blouse and did not damage the fabric in any way. I don't know where you can get phosphoric acid for home use, but I suppose it's been replaced because of environmental concerns. We're renting an old house while ours is being built. I'll have to toss our copper laced towels, sheets, underwear, socks, etc when we move. Bummer!