When I use 80% cotton cotton batting, I don't want the batting to shrink after the quilt is quilted.I always prewash my fabrics - so I prewash the batting, too. I fill the machine tub with warm water, soak the batting THOROUGHLY, then spin the water out. I don't agitate. Then I lift the batting out carefully - I don't want it to stretch or catch on anything. Dry it in the dryer.