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.

Years and years ago, a Ben Franklin store was discontinuing their Mountain Mist batts. So I bought 40 of the 90x108" size for $3.00 each. I really love them for hand quilting. I was moving a lot then and used them as fillers in the trucks to keep furniture from getting scratched. I'm down to 12 now. I use Warm and Natural for machine quilting but I still keep the frame set up in the living room with a quilt in it. That old frame is almost 125 years old now and has quilted many a quilt in its day. I consider it a part of my living room decor and my cats think of it as one huge cat hammock....lol. Every morning I have to tighten the ratchets to get the sag out.

I grew up with my mom and grandmother making quilts. I never saw them prewash batting. I have never heard of prewashing batting. Like the other post. I like the effect you get after washing your quilt. I love the popcorn look.

Warm and Natural here too. I never prewash. I like the look that quilts get when they aren't prewashed before making. They have that "older" than they are look! lol I don't like the look of brand new/crisp it makes it "unusable"!