Too keep fat quarters from fraying or getting wonky in the wash, I fold all edges to the inside and then fold it into a small square use a saftey pin to pin the center together, then put in a lingerie bag and wash and dry. Take out and iron. no shredded edges.
I also do this with yardage, and place pins all around the outside edge, comes out of dryer in the same shape as when you put it in washer. Just unfold and iron. No twisted fabric. The inside will be damp, so iron right away.
I just washed & dried a 5 yard piece of black fabric and it came out beautiful.