Hmm so I bought an Emile Henry Glazed Pizza Stone and my first attempt had a cheese overflow. I'd read you could use Bon Ami/Bar Keeps Friend to clean it on the Amazon site where I purchased it. It appeard totally clean after although I noted some areas that seemed a bit darker glazed and assumed it was from the heat. Nope, next time I used it, orange oil oozed from the stone and I kept thinking great I'm now going to eat Bon Ami oil... I ended up buffing as much as possible off the hot stone and pouring a heap of cornmeal to try to make a barrier between the grease and the pizza my hungry family was waiting for and still worrying about using the stone... so, don't use anything to clean it that you wouldn't want to end up in your food later.