I never pre-shrink my batting. I use Warm & Natural, 100%. I do pre-shrink my fabric for a variety of reasons but not batting. I like the crinkled look of the quilts and not pre-shrinking the batting (and using 100%) helps with this process. There was another thread here on the board quite a while ago about this very subject. You could do a search to see the responses there. If I remember correctly some folks had issues pre-shrinking batting. It's best to read your package label.