Disclosed is a method for extracting a desired metal contained in electronic waste having a substrate and desired metal integrally formed with copper, the method includes (a) contacting the electronic waste with a cupric amine solution to separate the desired metal integrally formed with copper from the substrate and the copper, and (b) optionally providing ultrasound energy at a frequency ranging from 15 to 45 KHz and at a temperature ranging from 45° C. to 60° C. thereby limiting metallic oxide(s) formation at a surface of a workface; and (c) etching the copper with the cupric amine solution at a temperature ranging from 45° C. to 60° C. for between 40 to 70 hours thereby releasing the desired metal from the substrate and the copper; (d) collecting the released desired metal of step (c).