For pieces smaller than a fat quarter (which I don't often deal with), I soak in warm water for awhile with a bit of Woolite, rinse, spin in a nylon mesh bag in the washer and hang to dry. Squares will shrink unevenly and no longer be square, so you will have to trim to another size. I will use a color catcher if I'm washing mixed colors together, or a multi-color print with a strong red. I did try the retayne once, with a red batik, but I don't worry about colorfastness in general (which maybe I should).