As a general rule we don't wash them. Last season we had a Barney's pack bag pick up a bunch of dall sheep fat and man did that stink! I guess it's the lanolin or something, anyway not washing it was no longer an option at that point. I took it off the pack frame, and ran it thru the washing machine inside a mesh laundry bag twice. Line dried, and it was good as new. No shrinking whatsoever, and it went back on the frame without problems. Nice to know it can be done in a pinch!