Review on Clover 4710 Pen Style Chaco Liner in Blue by Joyce Keesling

I already had the one with white chalk so thought blue would be useful. NO! I first used it on a quilt to mark quilting lines on my long arm. When I finished the first part I tried to shake it off. It didn't shake off. The client I quilted it for washed the comforter in cold water and dried it four times and the lines are still visible. I've tried emailing Clover twice. I haven't received an answer yet.