Originally Posted by Moonpi
Did you notice before it went in the dryer? Heat can set some marks.
I have some flat yellow tailors chalk that I am scared to use because it seems waxy.
if that is the flat chalk that is wedge-shaped on two sides and doesn't feel at all like 'chalk' but more like crayons, then i have had good luck using it for dressmaking. that stuff has to be pressed. i know it sounds like the stuff will melt and leave a smear, but i never found that to be true. try it on some scraps. please let us know what your results are. i have all colors and i never thought to use them for marking quilts. of course, i would have to find them first.