This ball point pen irons away! You can use this when marking a grid for pattern layouts, such as Christmas Ribbons, Melissa's Quilt or Hope's Diamond. Use the Quilter's Chalk Line for fabrics other than white, but on white fabrics, the pen works great! Iron on your fusible appliqué and your grid markings are gone. The markings do come back in cold temperatures so only use in places the markings will be covered with appliqué.