Have you seen the new Crayon Melter? You put the crayon in the pen and it melts the crayon just enough that you can draw with it and get the melted look. The color does not run. You can break the crayon to use only a little of that color at one time. An artist that I watched use this had about a dozen heated up at one time. She worked on canvas and said it worked great on fabric. I haven't tried it but regular Crayola Crayons stay on fabric after washing.