Salmen Master Oil Stone.

[Charles Guest]

An oilstone used with a petroleum based oil and wiped down after use simply cannot cake. Even if not wiped it's hard for it to cake. If there was a solid, caked-on grunge I suspect the stone was used with a vegetable oil like linseed oil or something else. These are drying oils and hence the 'caking.' If the stones were used with linseed oil that's an immediate tip off that the last person to use it was anything but a fine craftsman.

The chances that a bona fide craftsman would let his daily go-to stone go completely to pot are just about nil, as are the chances a recently bought stone off EBay came out of the operation of a just-retired or perhaps recently deceased fine craftsman. If this were the case you'd probably see the entire kit coming to market and a reference in each item's description about the craftsman and the other items up for auction out of his kit.