I love Color Catchers!!! I prewash all fabric, using Color Catchers. They are especially great with raggy quilts because you don't prewash the fabric for those. I made a raggy quilt using red, white and black fabrics (for an NC State grandson.) No problem at all with bleeding.
I also use Color Catchers in all laundry when there are any colored garments in the load. Has saved many clothes!