It's just whatt it sounds like....use pieces of unwanted items to stuff the hat. You can stuff with whatever you normally like to use, too but this is great way to use up those little tiny fabric scraps and other things. Like DH is always getting a hole in the back of his socks, and I started saving those and cutting them into pieces to stuff some of my smaller ornaments and things for Christmas. The rags make them tougher I think and they don't clump and do things that poly fill does.