Onions didn’t work fast enough in putting a patina on that $11 Mora Classic and I was thinking why didn’t the patina I expected develop? ... warmth and humidity. I was on a South Pacific island when this technique worked so well. So I warmed the blade over my kettle while boiling water for coffee. The blade became warm and had warm water on it. Then I wrapped it in a paper towel soaked in a little apple cider vinegar, set it aside and drank my coffee. When I saw it again the paper towel had a reddish discoloration which was concerning, but it was just the paper.

The steel had the gray patina I was hoping for, so I washed it, dried it and then treated it with Camellia Seed Oil, which is also referred to as Camellia oleifera and Tea Seed Oil (not Tea Tree Oil). From what I’ve read, it’s food grade so should be suitable for a carbon steel knife used in preparing food and is also used on woodworking tools in Japan. FWIW, $.02