Metal has no odor and you can't smell it. But what are we smelling then? It turns out that it's mostly a chemical called 1-octen-3-one, which is generated when your skin oils react with metal that you've touched. I thought this was really interesting, and I decided to try making pure 1-octen-3-one myself and to see what it smelled like. Procedure: https://www.sciencedirect.com/science/article/pii/S004040390202004X Background info: https://www.nature.com/news/2006/061023/full/news061023-7.ht