I made my first quilt way back in 1976...have made literally hundreds of quilts- I have not yet ever pre-washed a batting of any kind, for any reason- there are so many factors that actually dictate how much a *finished* quilt will shrink- including the amount/type of quilting on the quilt, the fabrics, the batting...and so many great battings on the market- if a person is truly worried about their batting shrinking it is quite easy to just buy one that does not shrink- I simply can not imagine even considering pre-washing a batting. if i'm using a pre-packaged batting I simply remove it from the package- unfold it, give it a couple good shakes, & drape it over a table for a bit while I load the quilt- or if quilting on the domestic machine- creating a sandwich- I may lay it out for a few hours to relax the creases before beginning- that's about all the 'extra' I've ever done with a batting. I love hobbs batts and use them a lot.