Griffith Oxalic Acid 6 Oz. Can Orders over $100.00 are usually shipped within 24 hrs of receipt (excluding weekends). The estimated delivery dates showing on Amazon are usually delivered much sooner than the dates shown. Great for cleaning most quartz crystals. 2 Tb. to one gallon of distilled water-heated (not boiling) will leach out iron stains from most quartz crystals. Alternately heating and cooling the solution with the crystal in it may be necessary, but 1/2 hour is generally all it takes. Free Shipping!!! Used by Professional Jewelers