I tried using upholstery cleaner on the pad but that didn't work. Here is a quick way to cover it. Cut a piece of fabric about 1" bigger then the pad. Using a tracing wheel along the edge between the mat and the pad will poke the fabric underneath the pad. It will stay in place and easy to pull out when you want to replace it. I used a bright batik to cover mine and it's pretty. A thin solid will allow the grid lines to show through if you need those.