Our bags are knitted with 100% wool yarn. The bags are then felted. Felting is the art of shrinking your knitting. It creates a fabric form of wool. Felted knitting is very durable and quite water resistant. A light brushing with a bristle clothes brush from time-to-time will remove surface soil, but eventually most items need to be washed. Do not use the machine for washing unless you want more shrinkage. Instead, hand wash the item in cold water as you would wash a wool sweater, then block and dry.