UPDATE: I emailed the manufacturer and heard back yesterday. She suggested I dab the areas with a 50/50 solution of white vinegar and water. I used a soft toothbrush to apply it. While wetting the quilt with the liquid it wasn't apparent that it was working (perhaps because the chalk had seeped into the batting) but when it was dry the blue was no longer visible. YAY!
Today I'll try to take a picture and post it.
Thanks for all you suggestiong...gotta get some of that Dawn dish detergent because it seems to have magic properties (even though they were not needed this time).