Today I just finished spending several hours cleaning gummy vegetable oil from a tri-stone that was given to me for free by a kitchen manager due to the fact it was useless due to the vegetable oil build up.
The stone was actually given to me 20+ years ago after I'd tried to clean it by running it through a dish sanitizer 20 or more times and scraping off the build up - which didn't work.
It was then given to me as a lost cause. I took it home and tried several times to clean the surface of the stones with dish washing detergent (Dawn), soaking, more scrapping, running it through my home dishwasher, scrubbing with GO-JO, and lots of elbow grease, it worked, but only partially, the edges of the stones were still unusable.
I then put it away for 20 years.
Yesterday I took it out of storage and disassembled it. This morning I boiled everything, case and all. This made some of the oil build up softer, so I scrapped it off. It also made much of it extremely sticky. It did nothing to make the stones more usable.
I then scrubbed them (and the case and metal pieces) with Ajax Cleanser (or the equivalent - Bon Ami?). This removed more of the oil and made them more usable but still didn't clean the stones or the other components completely. I felt the next step was going to be using wet dry sandpaper on the stones to remove some of the surface.
However while taking a break from my scrubbing I logged onto the internet and did what I should have done to begin with; I searched for "cleaning off vegetable oil build up" and found that I should have been using an alkaline cleaner. I started with the mildest version of these that I had - baking soda. I boiled everything except the case in baking soda water.
While everything else was boiling I tried cleaning the buildup that was still on the case off with a backing soda / water paste. It worked!
Then I took all the parts and the stones out of the now brown colored water and easily scrubbed off the build up that was left with a green pad and some more baking soda water paste.
So now I finally have a usable tri-stone after only 20+ years.
The moral of this story is "DON'T USE VEGETABLE OIL ON YOUR SHARPENING STONES"
A Japanese water stone is a softer stone and while sharpening on it you remove a small layer from it also. Due to this you sharpen on a new surface all the time. Never use oil on one of these stones as it will clog the stone and destroy it.
But back to your original question - as far as the using of water instead of oil on these stones - it works exactly the same as the oil does and provides a substance for the metal shavings to be suspended in instead of staying in the stone.
You can use water instead of oil on a oil stone also. It will work the same as the oil. -Unless you've already used oil on the stone. As oil repels water they don't work well together, and the oil that soaked into the stone will cause problems.
If you've already used oil it's better to stick with it, or run the stone through a dish washing machine several times to hopefully remove the oil - getting the oil out is very difficult.
Edited by Dropkick - 2/3/13 at 8:48pm