The sulphide layer that develops is quite non-volatile, so that likely wasn't a direct source of the smell. It would likely be another organic compound and the

The sulphide layer that develops is quite non-volatile, so that likely wasn't a direct source of the smell. It would likely be another organic compound and there is a known mechanism for iron. Compounds in our skin and sweat can react with the iron producing carbonyl- and organophosphine compounds. [0] Those compounds are more volatile than the original biomolecules and are quickly detected by our nose, possibly as an evolutionary response to blood. Similar processes would surely happen with other metal surfaces, and having a sulphide layer may even play a role providing reaction sites. [0]: https://phys.org/news/2006-10-iron.html https://phys.org/news/2006-10-iron.html