I just heard back from Clover. They suggested using an eraser and if that didn't work to try using laundry detergent.
They also reminded me that if I set it with an iron it will be permanent. I am so thankful that I did not do that.
I put a lot of lines on this quilt and don't want to stretch it out of shape. Best laid plans of mice and quilters.... lol!
To their praise, Clover returned an email to me with in about an hour. I emailed them a message from their website.
Thank you everyone for your help. I will let you know later if it works. Pretty sure I have an old toothbrush.