As I do with all my new fabrics I wash everything in HOT water (because I want to cover all the basis when the new owner has it.... no surprises!). I put each piece, or color group into a plastic bin in my utility sink and soak it there in hot water. Any piece that bleeds goes into cold water with some salt (in the bin) and that seems to take care of the problem. I use batiks a lot and find that sometimes a very strong color will bleed, but not more than the average of non-batiks. I also put every material thru a hot dryer after checking for color fastness in order to shrink it if its going to shrink, before I put it into a quilt. I try to make sure they won't distort in color or shape, but then a lot of my quilts go to childen with busy moms who use the washer/dryers frequently.