you can oil it, and rub it against another fine stone to clean it. You can also go to a machine shop, and ask them if you can have a cup full of the dust that has accumulated under their bench grinder..... make a slurry with kerosene, apply the slurry to a flat piece of steel and work your stone around on it. In both cases, rinse well with a good solvent.
Benning, me lad- what is with the Zombie threads? Why all the undead? Did you get caught in a time warp? Flux capacitor on the DeLorean acting up, and you are trying to send a message to us? What is it, Lassie? Did Timmy fall down the well again? (Arrrffff!)