The short answer is that you can prewash most batting – but that you don't actually have to. ... Batting that isn't really batting at all – old wooly blankets or quilts come to mind – does need to be washed thoroughly to prevent shrinking and the problems associated with it.

How do you clean batting before quilting?

Fill the washing machine with water. Unfold and submerge the batting in the water and turn the machine off! DON'T AGITATE! Allow the batting to soak for a while and then spin the moisture out.

How do you pre shrink a wadding?

She discovered that they all shrink, even poly batting and those that are supposedly pre-shrunk. Consequently, she developed a method for pre-shrinking batting by letting it soak in the washer (never agitate it) and then spinning the water out. The batting is dried to an almost-dry state in the dryer.