Betsy's Closet Quilt blues :(

I decided to practice my free motion quilting on my Betsy's Closet quilt so I used a Dritz blue chalk marker to mark my line....  didn't realize that the blue marks would not come out of the quilt easily.  I washed it 3 time and it's still there.  Very disappointed in a chalk marker that is marketed for quilters. Seems like they would test their product so that we wouldn't ruin our quilts we worked so hard on.  Oh well, here it is after three washing's :(