Treat Tealbee products like your coziest wool sweaters.  Wash in cold or warm water in a gentle cycle and tumble dry on low. Never in hot water or hot dryer. For absolute best care, wash in a delicates wash bag and line dry.  We only use natural bamboo and cotton fabric, never synthetic. Although we use pre-washed fabric to minimize shrinkage, we design all our products with 5% shrinkage in mind after a wash. Just like wool, it might pill (tiny balls that gather on the surface), but it has no impact on warmth or comfort of the sleep sack. It just gets cozier over time.