Rather than a small bottle of oil, get two zip top bags, and put a small cotton or camios rag in each one. You can go smaller, but equal to blade lenth square is what I like. Soak one of the rags with food grade mineral oil. An ounce or two should do it. Since I live in the desert I wipe with the wetter one first, then the dry one. Eventually the dry one will leave a perfect not wet film on the blade. Food grade mineral oil will not go rancid, and allow you not worry about petrochemicals and meat. If your knife has a wood or leather handle, mineral oil will help preserve the material. Google patina, and you will find people using mustard, coffee, vinegar, ect to do it. Wipe the blade down with alcohol first. The issue is that home grown patinas are inconsistant, at best. I have a bottle of oxphoblue cream that I got from brownells for like $15 that will cold blue steel w/o much issue.
I was scared of sharpening my D2 benchmade blade, since it was hardened to 62RC. I was amazed at how easily I was able to get it back to scary sharp, and held that edge for a long,long time.
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