Bread-Bakers v100.n058.9

I'm hoping someone out there will have a way to help with this:  The father
of a good friend of mine used one of my stoneware pizza rounds, and
unfortunately he sprayed it with oil (I guess to help the dough not stick).
Does anyone have a way I can get the oil off?  He also put it in a
dishwasher.  The stoneware looks glazed now.  It still bakes ok, I just don't
get the same results I did pre-greasing.  Any help or ideas?  Many thanks!

Yvonne  (who will bake pizzas *for* my friend's dad in future!!)