tl;dr Metal/rust do not give off any smell, and even if they do, they would be odorless. The smell you associate with metal (coins, nails, etc) are actually formed when you touch the metal, at which point the metal acts as a catalyst to speed up oxidation of your skin oils, which forms odorful (?) molecules. So you are really just smelling yourself. The predominant compound attributed to the smell is 1-octen-3-one. The rest of the video is him trying to create and isolate this compound.