I had this happen with the blue chalko liner and a water soluble graphite pencil. However, it wasn't that the blue and graphite didn't wash out of my quilt but the blue chalk and graphite had embedded in the quilting thread. The blue was hand quilted the graphite machine quilted. I never did get the blue all the way but gifted the quilt anyway. The graphite I washed several times. First plain water then detergent and oxyclean. I also let the quilt soak in the washer for a while. Finally I went at it with a soft bristle toothbrush. I don't think I got it all the way out but it faded to the point it was not noticible except by me. The blue one I gave it to my mom so I don't know if it eventually washed out. I don't think it did. The thread is much more "pourous" for lack of a better term, then fabric. I think the powder just clings to all the microscopic fibers sticking out all over on the thread and because it is sunk down in the fabric, water and detergents just can't get to it.