Hi.Here in the U.K we call muslin calico,that often causes confusion.I buy unbleached medium weight then wash it on the highest heat in my machine.This result in a lovely 'crinkled' feel,wonderful to quilt either by hand or machine.I can only find one place to purchace it however as most quilt shops sell the bleached pre shrunk calico. That is almost always more expensive too ! I would look for mill shops but have no idea if you can find them in the U.S. Happy quilting,Letty