How do you get black denim to stop bleeding onto other fabrics?

Question

I am making slip covers for my couches and decided to go with black denim, because I like the way it looks. I pre-washed the denim and took it out of the dryer, but it still left blue smudges on the white towel I rubbed on it. So I washed it again, and again, and again. And it still leaves marks on white fabric when dry.

I really want to keep this fabric, but I don't want to have mine and my guests clothes stained from sitting on my couch. Or end up waking from a couch nap and going to work with blue stains on my face. Is there any color sealant technique or product I can use to make the bleeding stop already?

I have already tried salt in the wash, those dye-catcher sheets, and oxy clean liquid. I'm about to try an overnight soak with white vinegar as a last resort.

Answer 1

Put your denim fabric in very hot water in your bath tub and two cups of vinegar + one cup of pickling salt, let it soak overnight.  Hot water sets the color.  To keep the water temperature hot keep adding a kettle of boiling water from  time to time.

If this does not work - I think you are out of luck

Answer 2

Check out this web site.  It has several methods for setting color in fabrics.  I know it relates to fabrics that you dye yourself, but it might give you some ideas that may help.  

http://www.prochemical.com/productuse.ht...