They will work, but I think it is safer to use them along with Synthrapol. Synthrapol is simply a specialized detergent that will allow unset dye particles to remain suspended in water so they can be rinsed away instead of settling into other fabrics. Synthrapol is widely available in quilt stores that cater to dyers, or can be ordered online. Amazon has it.
You would not want to use Retayne on a finished quilt anyway. Retayne is supposed to be used on yardage before it is used in a quilt. Retayne permanently sets dyes, so it will permanently set a bleed if you wash an entire quilt in it!
Edit: Just want to add that color catchers trap unset dye particles. Synthrapol allows unset dye particles to remain suspended in water. I recommend using both in case there is an excessive bleed -- more than the color catchers can handle. In that case, the Synthrapol allows a second line of defense.
Just be aware that Synthrapol requires a *lot* of hot water to use. It is not effective in a home front loader because there isn't enough water; a home top loader is fine, as is a medium or large laundromat front loader.
Last edited by Prism99; 10-01-2012 at 08:21 AM.