I own several carbon steel knives and am concerned with with rust prevention. I also own a bicycle shop, and one of the newer chain lubes on the market is Boeshield. It is a wax base lube dissolved in a VERY volatile carrier so it penetrates as quickly and deeply as WD40, but when the carrier evaporates it leaves behind a pretty substantial wax coating that contains some dry lubricants as well. Seems really promising for lubrication/protection.