I know, really stupid or "basic" question: I tried Sea Buff, an eraser, toothpaste and rubbing alcohol to erase my pencil writing on a plastic slate. It looks like I could probably clean it in an hour of vigorous scrubbing, but there must be a more efficient, less ridiculous solution.
I cut them in half and they're a one time use. A half pad will work a couple of times if you're not cleaning too many multi page slates. I keep the unused ones in a zip lock bag. They're cheap and I have a ready supply under the kitchen sink.