As a rule i don't prewash as i don't like the wrinkles and I hate to iron--I'm admittingly lazy. So that said i use the color catchers with any new fabric or article of clothing in case there is bleeding. I've had color catchers turn colors everytime I wash. Greens have been my worst at leeching into the water. I'm not sure it is the fabric or the quality of the dye, or how much over dying is done. Some fabrics have a stiff feel and it is mostly from the dye.