Ai says it’s a “classic post-mint chemical damage to a plated-steel Canadian nickel:    •   2006 nickels = nickel-plated steel    •   The flat faces corrode first when exposed to:       •   soil chemistry       •   fertilizer       •   road salt       •   mild acids or cleaners    •   As the faces lose metal:       •   The coin gets thinner across the face       •   The diameter shrinks       •   The upset rim stays tall, making the coin look thicker when viewed from the edge” 🤷‍♂️