This discussion could really use it's own thread, but it seems there are only three of us really interested in it ATM so...
The edge width figures from the Verhoeven document were measured as a maximum width from one peak to another, on what looks like a zig zagging line. The valleys of that zig zag are much closer together than the 3 um, or even the 1 um, measurement (and especially if diamond abrasives are used).
So there is still a sub micron edge at those lower grits, it's just out of alignment and mostly unusable in that condition.
(One could also make a case that sharpening stops where a usable edge is obtained for the intended cutting media i.e. a pocketknife does not need the edge that a razor has.)
As for cleaning stones, I rinse my stones off with water. Hones (artificial stones), on the otherhand, (ceramic but not Shapton) require periodic scrubbing with a stiff nylon bristled brush under running water, or a good lapping; mine are cheap so lapping is usually the preferred method.