flannel shrinks quite a bit and for more than one wash, if you are concerned about shrinkage go ahead and pre-wash the flannel once, toss it in the dryer, it will be nice and soft when it comes out; you will need to either use steam or starch when pressing it. it will still fray just fine when you make your rag quilt since you clip it. it is best to take them to a laundrymat if they are big, and i usually take them outside and give it a good shake before putting in the dryer. if it's a big raggy quilt i usually empty the lint trap in the dryer 1/2 way through too, it builds up fast. if it seems like there is alot of loose threads i take it out of the dryer and back outside to shake then back to finish drying.