Useless fact
Why do my hands smell like metal after touching coins?
The metallic smell on your hands after touching coins is actually a type of human body odor triggered by the chemical reaction with the metal.
Why this is true — Scientific research, notably a 2006 study published in the journal Angewandte Chemie, demonstrated that the 'metallic' smell is 1-octen-3-one, a compound produced when skin lipids break down upon contact with iron or copper.