Well, I tried the blue Chaco Liner Pen on a scrap piece of fabric and it washed right out.
Then after I used it on the quilt, quilted, and then washed the quilt, some of the blue is still there. I really think it stained or dyed my white quilting thread blue. It's not too bad but I can tell it's there.
I tried shout but that didn't get it all. I read on a blog (can't remember whose) to use green dish detergent mixed with something. Unfortunately, I can't remember what that something was. So tomorrow I am going to try green dish soap. I'll let you know how it goes.
Happy snipping, stitching, and quilting!