no matter what you are using to mark your quilts, no matter how many times in the past you have used the same tool...you should ALWAYS test on EVERY new project before marking...i use chalk alot, sometimes pencil...but i always check to make sure it is going to come out...and always remember to NOT PRESS after marking...sometimes that will set what ever you are using so it will never come out....always test first...save yourself frustration later.