Gold or fely powdered ore. Hydrochloric acid. Nitric acid. Formic acid. Sodium sulfite or sodium bisulfite. Tap water and distilled water. Un-iodized Salt. How To Use Aqua Regia To Purify Gold. Place your gold or fely powdered ore a Pyrex contaer breaker. Mix 1 part nitric acid to 3 parts hydrochloric acid a separate glass or plastic contaer.