If your oilstone needs leveling, says the " Blacksmith and Wheelwright," scrape it with the edge of a piece of glass. A piece of glass can always be obtained when perhaps the ordinary methods of rubbing down are not available or would take too much time. If one end or one corner of the stone stands higher than the rest it is easier to reduce to a general level in this way than by the ordinary methods which make the surface flat, but cannot easily remove a slope to one end or one side.
A slight inclination in any direction causes the oil to run off the stone, and it is advisable, therefore, always to leave the stone slightly hollow so that the oil will tend to run to the middle when it is left standing. The greatest wear occurs, not in the middle of a stone but near the end at the places where the movement of the tool is reversed. It is, therefore, chiefly a small area at the extreme ends which require scraping down and sometimes a little in the middle and along the sides, to take some of the hollowness out.