I prefer not to wash, but you do run the risk of colors bleeding. There is a liquid product you can find at quilt shops and online (I can't think of the name off hand) that helps prevent bleeding. I haven't used it myself, but my sister-in-law uses it all the time.
:arrow: Comments from those who have used it???
I do use Color Catcher with my clothes, but it's not 100%. I've started tearing it into three pieces to maximize contact in the washing maching.
I know you can premordant wool with alum to help color "stick" to the fibers when dying. I wonder if you could make your own color catcher with cotton????? :roll: