Perhaps a bit late after all the postings, but I read the post by Charisma and related. I have just completed a wall hanging from batiks with a light blue background. I used blue chalk to line out 1" diagonal lines to quilt. Used white thread to quilt. Could not get rid of those darn blue lines. This afternoon I sprayed the piece with "Spray and Wash" and said a little prayer and tossed it into the laundry.....after much pacing around and waiting...I took it out of the washer and the blue lines were gone! Voila! Happy ME! Doubt I will use the chalk again tho....