I haven't pre-washed for over 20 years...and don't plan on going back to it...love working with the fabrics that still have their finishes in them...they sew so much better. I have never had a problem with bleeding...but...I only wash quilts later in warm water...never hot, and I never leave a wet quilt just sitting, always am right there to get the quilt to the rinse cycle, rinse several times, then spin and either lay flat to dry, or hang outside with a sheet over to protect the quilt, and some quilts I will throw in the dryer at least for part of the drying time.