ive been making quilts since 1976...and have never yet pre-washed a batt and do not intend to....it is something i simply can not get my mind around-seems like such a lot of work...there is a vast selection of batts on the market- if i don't want batting shrinkage i buy a batt that doesn't shrink...if i want a flat one =that's what i buy- if i want lofty---yup you guessed it- i buy a lofty batt...i just dont get the whole---prewashing a batt (mindset) in the 36 years of quilting i've never has a quilt come out that i thought a pre-washed batt would have been better...simply stumped by the whole topic...