I'm a prewasher as well. Probably comes from my garment sewing days. But it's also what I was told when I first started quilting. I use my regular laundry detergent - happens to be Arm & Hammer powder, in warm water and sort by relavent colors same as I do my normal laundry. I do not wash it with my laundry as I use softener for my clothing but not my fabric. Prewashing removes all sizing, chemicals, etc. and hopefully you discover any drastic fading/shrinkage in the process. I then dry in my dryer. Interestingly enough, I took a serger class from a LQS a few months ago and the instructor (also a quilter) mentioned that unless you are drying your fabric with a FULL LOAD of laundry you don't necessarily get the full shrink rate as it does not take as long to dry even a couple of yards of fabric as it does a full load of clothing. I haven't bothered with that but it does make sense to me. I then wash with detergent and softener when the quilt is completed. Getting the 'crinkly' look that I love with the batting shrinkage.