Originally Posted by no1jan
I prewash my fabric but have never heard of anyone washing batting.
I ALWAYS prewash my batting if it's a shrinkable like cotton. I've never used wool, so I can't speak for how it would work for wool. But if you're going to wash the quilt after it's quilted, you should probably prewash the batting, or it's going to shrink.
I fill the washing machine with warm water, soak the batting, spin the water out. Then I dry the batting in the dryer. Cotton batting definitely shrinks, and I want it to shrink before I quilt it, unless I'm going for the 'antiquie' shrinky look.