I don't even bother with the washing machine. I put fabric in the bathtub with very hot water and a dab of detergent, then let it sit overnight. In the morning, I drain it and move it to the washing machine for a rinse & spin, then dry it in the dryer. I've never had a fabric bleed after doing this.
I learned this technique from a hand-dyer. This is how she treats her fabrics after she dyes them.