So do the lines reappear over and over again?
This would annoy me.
Seems like there is chemical reaction going on that does not dissipate. Makes me wonder what it is...
Sometimes I just wing it and don't even mark my quilts when I hand quilt. Makes for some interesting stuff that I sometimes have to re-do. But then I have gotten a whole lot better judging my spacing.
An Amish quilter I met told me to just use graphite and a mechanical pencil and then I erase it. I am very judicious in my use, though!