Thanks for the hint about the surfactants in the detergents. I usually actually do not pre-wash. I just did on my blues and reds this time as I was using up some larger scraps that I think I picked up at a quilt guild meeting free table. Both the dark blue and the reds did shed dye unto the color catchers and I went them through the washer twice. I am not prewashing the light blue and the neutrals. I have mixed pre-washed and un-washed fabrics before and it still came out OK. I used to prewash all the fabric I got and I still have some of that left in the stash. I remember when I used to go into a fabric store and my eyes would burn from the finishing chemicals in the fabric. Better now I think. I do buy the expensive fabric (mostly when they are sale). I have found some of the fabric from chain stores really needs to be prewashed mainly for me because some of them really shrink. I do remember getting a piece of fabric from a chain store because that is the only place I could find the color I wanted. When I bought it, it had a good feel to it. After washing it, it felt like a limp piece of cheesecloth. Must of been treated with heavy duty finishing spray or something.