[en]We study the role played by coin experts, called moneychangers, in the metallic money system. To do that, we introduce intermediaries that can expertise and certify coins into the VeldeWeber and Wright’s (1999) model of commodity money with imperfectly recognizable coins. We show under which conditions buyers have their coins certified, how circulation by weight and circulation by tale equilibria are affected by moneychangers, and whether moneychangers increase welfare.[/en]