Lynneander

I need some advice on removing pencil markings. Yesterday I was marking a quilt for a group project with the ladies I sew with. Another woman offered to help mark and I was grateful for another set of hands! When she removed the stencil, I was speechless. She had marked so heavily (with pencil) that I knew right away that I had a problem. I didn't say anything, but called it a day and took the quilt home under the guise of working on it a little more. Actually I wanted to try to remove the markings. I put the quilt in a handwash and all the markings came out except for the dark ones. They are lighter, but still clearly visible. I don't know what to do next ... HELP! Any advice will be so greatly appreciated!!