I would cut a tiny piece of the fabrics you suspect. put them in closed container with hot water and detergent and shake it for a time like the washing machine. Rinse and place the small pieces on a white paper towel. That way you can find out who the culprit is. I put a color catcher in my laundry with all shirt I have washed numerous times before and it still came out a gray cast on it. This is the method that I learn from taking a quilting class from Harriet Hargrave.