Cleaning an oilstone
It's a piece of rock, for heavens' sake. The few times I've had to clean mine were done with dishwashing detergent and water. I like the idea of scrubbing with a toothbrush, though.
After cleaning with any effective cleanser, and allowing to dry, the stone needs to be re-oiled. I always used Buck honing oil, until I found Singer sewing machine oil was cheaper. Whatever oil you use, avoid 3-in-one, as it has a high paraffin content that will just clog yr stone right up again.
I'm pretty much of a traditionalist, but frankly, since diamond sharpeners became common and fairly cheap, I don't use an oil stone much any more. As an old traditionalist (He was one of those dress-up-and-play-middle-ages guys) to whom I confessed this, then remarked, "Once in a while, just once in a while, technology wins one."