I stumbled on this property of many metals the other day and found it very interesting especially since my wife and kids are always thelling me my horns are gross and germ ridden. I thought you might find it interesting as well. The oligodynamic effect (Greek: oligos = few, Greek: dynamis = force) was discovered in 1893 by the Swiss Karl Wilhelm von Nägeli as a toxic effect of metal ions on living cells, algae, molds, spores, fungi, viruses, prokaryotic and eukaryotic microorganisms, even in relatively low concentrations. This antimicrobial effect is shown by ions of silver, copper, brass, gold, other metals. Many infections can be spread by doorknobs. Brass doorknobs disinfect themselves in about eight hours, while stainless steel and aluminum knobs never do. Unvarnished brass doorknobs therefore tend to be more sanitary than stainless or aluminum doorknobs. The effect is important in hospitals, and useful in any building. Silver is capable of rendering stored drinking water potable for several months. For this reason, water tanks on ships and airplanes are often "silvered".