General's Pastel Chalk Pencil is a mixture of chalk and clay. The chalk will generally rub off while you are quilting, however the clay lines will remain on your top for the duration of the quilting (machine quilting will often remove more than hand quilting). When finished the remaining chalk and clay can be brushed off with a terry-cloth washcloth, erased with a fabric eraser or washed in cool water. General's Pastel Chalk Pencils contain no chemicals and are of archival quality.