The color cathchers. I have had great luck with them. The lady that told me about them said she did not prewash her fabric and so when she finished a quilt she washed it first with one or two color catchers. She said she never had a problem. I am back to prewashing after the thread that talked about the dyes and chemicals in the new fabric. I fold the fabric to store it and when I am ready to use it, I iron it with startch.