I have used Crayola Washable markers very successfully. I always wash my fabric before using it. I marked my quilts using a stencil and the washable markers, quilted them, put the binding on and then washed them. I used every dark color of marker - brown, purple, red, green, blue. I used a little laundry detergent in the wash water and had no problem with the marks. They are gone. I think if I were marking on white or off white I would make a very faint line with the markers just in case.