The Aqua Regia Gold & Platinum Refining System is often used to refine the gold found in e-scrap like circuit boards and chips.  The volume of non-metal plastics, ceramics and the like compare to the precious metal content is high-so much more acid is required to cover the material than is required to dissolve it.  So the most economical way to dissolve the metal is to remove the non-metals after the metal is dissolved and then add more e-scrap.

Having a second E-Scrap basket at the ready is a great way to save time and money when refining.