Originally Posted by tlcquiltnut
Do those work? Color catchers? I have used vinegar.
Color catchers only do what the name implies, they catch excess dyes from bleeding on other fabrics. They do NOT stop a bleeder from bleeding not do they set dyes. Unset dyes will continue to bleed and if you ever forget to use the color catcher with the bleeder, even if it has been washed with a color catcher before, it will bleed and run on to other fabrics.
Vinegar will not work with many of the modern dyes. Your best and safest bet is to use Retayne dye fixative when you do your initial prewash. You can buy it on line at Dharma trading and many LQS carry it.