i use warm and natural 80/20. i washed it on gentle, hot, then tumbled it, gently, hot. only did this once and that was enough for me. it came out very soft but very pilly. the pills didn't affect the finished quilt, but i had pills all over my room for weeks afterward. since i prewash all my fabric, i don't think i have to wash the batting. i don't think it shrinks enough (1%) to worry about.