Abstract: A method, comprising: in the presence of an acid, applying a current between a first electrode and a second electrode so as to form an amount of hydrogen peroxide in situ so as to give rise to a digesting solution that comprises hydrogen peroxide and the acid; contacting the digesting solution and a metallic composition comprising a metal so as dissolve at least some of the metal comprised in the metallic composition, the metal optionally being a transition metal; and collecting at least some of the metal dissolved from the metallic composition. A system, comprising: a container; a first electrode and a second electrode, the first electrode and the second electrode being disposed within the container, at least one of the first electrode and the second electrode comprising PbO2; and an amount of acid disposed in the container.