some colored chalk doesn't wash out well--I have trouble with both yellow and green. And had green Ultra Clean Markers not wash out either--but the owner said she'd starched it and that might have been the issue. I also use just plain white (steer clear of dust-free as it has a wax in it) chalk most of the time. recently at a machine quilters guild meeting we talked about using Golden Threads paper when needing to mark white fabrics with very specific designs.