My approach is to hand wash and give them a good long soak (hours or overnight) to let any loose dye get free of the fabric. (If a lot of dye comes out, I do a second wash and soak.) Rinse thoroughly, squeeze out what water I can (I don't bother with tight wringing.) and hang to dry. Iron while still damp. It takes a little more hand-on time then just throwing things into the washing machine, but there's no fraying with this method.