 ... More Best and Easiest way to refine gold dust to get 00.0% purity 0000-0-0 The black powder is gold. Dry it and melt it and you have 00.0% gold this way without the iron inside the metal. Anther way to refining gold 00.00% with any alloys: put 000 gram metal in beaker, then put in 0 liters of agua regia (0 HN00 + 0 HCL). Wait 0 day or More 