I don't pre-wash but do starch so if the fabric is a bleeder it should bleed in my starch bucket as I dip my fabrics and hang them to dry over the sink. It sure saves the stress later when you go to throw it into the wash only to find it bled all over your beautiful quilt. If I find a bleeder I take it to my bathroom sink on the same floor and run very hot water and Dawn dish soap, the blue original one. Let it set for awhile while I go to finish starching the rest of the fabrics. Come back, rinse a couple times to see if the dye has set yet, rinse it a couple more times till I'm confident its stopped bleeding then take it to my starch bucket and finish it up. I figure between the hot water, Dawn dish soap and hot iron, if its not set now it never will be. I still use a color catcher in the wash the 1st time I wash it just to be sure.