I use a lot of Perfection Tailors Chalk. It is actually a wax crayon and as long as you don't hit it with an iron, your lines don't disappear! And because I wash everything after I am done with it, there isn't any waxy residue. I can send you one if you want to try it out! Send me a pm with your address. I got a box of them thrown in when I bought my serger from a guy on CL.
http://www.amazon.com/Tailors-Chalk-.../dp/B004XZM4HA