I buy warm & natural/white wholesale... this is what their site says about warm & white
The soft, natural cotton goes through a gentle mechanical cleaning to pick out cotton plant and seed remnants. The tiny plant particles that remain lend a special look to crafts when used as an exterior fabric and will not damage your fabric when used in your quilt. Shrinkage will be about 3% with your first washing. Many quilters prefer not to pre-wash to achieve the unique effect created by the slight shrinkage of the batting when the completed quilt is washed. Please follow these directions if you wish to pre-wash your batt:
1.Hand wash in a basin or tub with a mild detergent. Do not agitate or spin in your washing machine.
2.Soak for 20 minutes, then rinse several times.
3.Squeeze water out. Rolling in a towel will help to remove excess water.
4.Dry in a cool or warm dryer or allow to dry flat.
Once quilted Warm & White cotton batting can be machine washed again and again without fear of separation or bunching.