Some Taylor’s chalk contain wax and do not wash out. Try any marking tool on scraps and try removing it before doing any marking. My favourite marking tool on medium to dark fabrics is white chalkboard chalk that I sharpen using a large pencil sharpener. Some like Crayola washable markers but again try to wash them out of a scrap before marking on your quilt. I do hand quilt on my Qsnap floor frame but you would need to not wrinkle your linen too much as it tends to hold wrinkles.