Using a whetstone can be a good idea if you do it right. You really should sand it pretty good first becasue you wouldn't want to use anything rougher than a hard arkansas stone. Also using oil on the stone is a bad idea because oil is a very bad thermal conductor. Because oil doesn't evaporate it would get left in the tiny nooks and crannys (mmmm..English Muffins) that the thermal grease is supposed to fill in for better conductivity.