Like billym I have a lot of knives. I have a few that are stainless but most are various grades of carbon steel. I don't oil my knives because I use them a lot for skinning and butchering game. If I am somewhere that I think they might rust because of humidity I coat them with corn or vegetable oil and allow it to dry (use two or three coats). When thickly coated and aloud to dry it forms a coating that will not allow the blade to rust and won't affect the leather of your sheath. It will last for at least a year (the longest I have kept one coated) and washes off easily with hot water. As for my folders I store them folded. If I do get some rust on my blades I use a plastic scouring pad and corn oil again to polish out the rust.