When I had a black fabric that refused to quit bleeding even after vinegar wash I decided to try something else, if it ruined the fabric it would be no loss as it was unusable the way it was. What I did was put the fabric in the biggest pot I have, fill with water, put on the stove and boil it hard for about 20 minutes. It didn't hurt the fabric and it did stop the bleeding. The finished quilt is black and white, has been washed several times, and the white is still white. No more bleeding.