Thanks, that would be helpful. I just checked on Amazon and found the Clover Chaco. Because it is a tone-in-tone light fabric, I need to use a color--probably blue. There are a lot of reviews that say they can't remove the Clover Chaco blue chalk. That scares me enough that I want to use something else--something that brushes right off. I only need to mark one block at a time, then, I want to brush it right off. Anyone use a colored chalk that brushes right off?