In combination with oil, some stones make a lubricious slurry which enhances their effectiveness. Porous stones e.g. the Norton India Combination Stone (No. 711053) are normally pre-saturated with oil and only need some drops of honing oil (No. 705263) on their surface before sharpening. Stones with closed pores absorb only small amounts of oil. A few drops of honing oil on their surface are enough. Unlike water, oil does not rinse the stone, it therefore clogs more quickly. It can be cleaned by wiping it with petroleum.