I had a real problem with shrinkage with a Northcott layer cake I bought recently. I didn't wash them, but wanted to starch them as I was going to be working with a lot of bias edges. Just by spraying them with spray starch, they shrank 1/2" in one direction, which meant I had to make my blocks smaller than I had anticipated because I was supposed to use a 10" square and ended up with 10" x 9.5". To say the least, I was very frustrated and don't plan on using a lot of precuts in the future.