I learned the hard way.....red.....sigh. I wash everything when it comes in the door and it is washed in warm water with detergent with 4-5 color catchers. I usually wash it with regular clothes that are in the same color family. Reds, blues, blacks, are usually the ones that bleed. However, washing with the color catchers, you know immediately if there are bleeding fabrics. Do another warm rinse with the color catchers. I put everything in the dryer for 10 minutes on low, gently lay out the still wettish fabrics and then hang everything up and fold up when dried. When I am ready to use the fabric, I iron with spray starch and steam iron. Anymore, almost all fabrics shrink, some a little and some a lot so I am hoping that all my quilts won't shrink or bleed.