I use the little chalk marker here - http://www.generations-quilt-patterns.com/chalk-pencils.html - I didn't get it from them, but that's the one. It has a little wheel in it, and puts down a very thin line of loose chalk.

I have this one and it has worked awesome for me, although I haven't used it alot yet. I plan to buy another one when I see them again at a show - wish they were coming to Quilt Canada in June!

I vote for the Bohin leads as well. I bought their mechanical pencil as all mine at home were too small. The markings stay on quite well but rub off relatively easily. Most wouls probably be gone by the time you are finished quilting but if not should wash off easily after the owner has bound and washed.

I use that Fons and Porter ceramic pen. It works great. There is a dark lead and a white lead.

Yes, this one stays on until it is washed or ironed out. I love the pen!!

I use chalk. I sharpen it with one of those eyeliner pencil sharpeners and do a very fine/light line.

I like General Chalk pencil in white and yellow. They are inexpensive and easy to sharpen like a pencil.

I have used the Clover gel pen and it does last until you iron it or wash it. Test, test, on a scrap if you can before you use on the real thing.

I love the Bohin white chalk mechanical pencil. It goes on in a very fine line. There is an eraser which will take it off but more than likely it will be worn off by the time you're finished. I only mark a section of machine quilting as moving the fabric around will eventually rub the markings off. I haven't tried the Fons and Porter ones but given the comments here that will be on my list to try especially for the dark markings. I am satisfied with the Bohin chalk for marking on dark though.

I just bought this one and used it. I love it and it irons off just like the frixion pens but works so much better on dark fabrics.