Ok, just wanted to thank everyone for all the suggestions. The blue chalk marks are from a "Blue Washout Pencil" (that's the actual name). If I remember correctly, I bought it at Walmart. I will never use these chalk pencils again! In the past I have used sidewalk chalk, and I will be going back to it when I start my next quilt. I came up with a concoction that seems to be working. In a spray bottle I mixed about a cup of white vinegar, filled the rest of the bottle with water, and added a good squeeze of Joy dish soap. I sprayed all the blue marks and rubbed it with a bar of Ivory soap. I let it soak in cold water. I am now going to wash in Tide and pray it comes out. This will be the 4th wash and each time it has gotten lighter. Hopefully, this is the final wash ! I will keep you all posted! (PS the marks are on white and light yellow boarders!)