On another site, I found this posting "I scotchguard the fabric side. " Sounds like a good idea so that the chalk doesn't ruin the beautiful fabric sides. On the same site, I found this regarding placemats "We made these for our church bazaar. 13X18 I used a one pound coffee can lid to round off the corners. I also stuck a loop of elastic under the left side edge (for the chalk) while i sewed the binding on. It worked well. We sold them 2 for 5.00 or $3 each. They turned out really cute. Next time i will make them 12 X 18 so i can get an even 9 mats out of a yard." and "I sold them on Ebay for $15 till I was tired of making them!
One Saturday I sold 11 of them. "