My DGD scribbled all over the middle of my large Olfa mat with a Sharpie. I didn't even try to remove the marks as I knew nothing would remove it completely. I bought a new one and took that one to my guild's free table. A member bought it and cut it up to make tote bottoms. So it was put to good use. I could have turned it over but didn't want to and no one at guild wanted a turned over mat either.