Marti Michell says to cut off a snip of fabric, wet it thoroughly and lay it on a white paper towel. If it turns color, then you know you need to wash it. I also have tons of Kaffe's fabric and plan on checking it all out. I have had very expensive name brand fabric bleed horribly, washed the fabric at least 6 times before it stopped. I am so thankful that I did not use it in a quilt before washing. I think quilters are in two camps about this, do what you feel you need to do.