Smart Stain is a strong, non-hazardous, fast drying, transparent patina system. It has no VOC and no odor. Smart Stain works on any metal or substrate as well as over patinas and other oxides. Smart Stain is made by combining finely ground, naturally occurring colored oxides with a water base polymer/resin binder. It is sold concentrated and may be diluted with distilled water up to 25% to increase transparency.