Tailor's chalk is used to mark fabric when it is being measured for sewing and alterations. Some tailor's chalks are made of a mixture of wax and chalk dust, and some are purely wax. It can take a little work to get the tailor's chalk out of your garments, depending on how long it has been sitting and what your garment is made of. Remove the tailor's chalk as soon as possible for best results.
Rub the tailor's chalk with some water and a sponge to see if it will come off easily.
Scrub a little harder with a toothbrush to remove the waxy chalk. Use a bit more water if necessary.
Rub at the chalk with a piece of flannel cloth.
Place a warm iron on your garment after laying it on an ironing board. The steam and heat from the iron should melt the wax from the tailor's chalk if the above steps don't work.