Silver is more than just an object of beauty.聽It鈥檚 the stuff of memories.聽Prior to digital photography, all picture taking relied on compounds of silver.聽The reduction of silver ions to metallic silver by the action of light that is at the heart of the chemistry of photography.聽Silver is in fact so light sensitive that a crystal of silver chloride could detect the light of a candle on the moon! That鈥檚 what they say anyway.聽I haven鈥檛 tried it.聽But I certainly have tried cleaning silver.聽The metal of course tarnishes.聽That鈥檚 because it reacts with small amounts of hydrogen sulfide in the air to form black silver sulfide.聽What鈥檚 the answer?
Well, you can remove it with a generous amount of elbow grease by rubbing with a fine abrasive.聽Or you can dip silver objects into a solution of thiourea and sulfuric acid to dissolve away the silver sulfide.聽Or you can make use of some very clever chemistry.聽Just wrap the silver to be cleaned in aluminum foil and drop it into a glass bowl filled with boiling water to which a spoonful of washing soda has been added.聽Within minutes the tarnish disappears.
There鈥檚 some remarkable chemistry going on here.聽The silver sulfide is converted back to metallic silver as the aluminum strips the sulfur away, forming aluminum sulfide.聽This method has the added advantage of not removing any silver at all.聽However the silver that gets redeposited may not shine as brightly as the original surface.聽So this method, while by far the easiest, may not be suitable for grandma鈥檚 fine jewelry.聽
While silver is a fine material for jewelry, it does not cure any disease. That may sound like a strange comment but recently聽鈥渘anosilver鈥� or 鈥渃olloidal silver鈥� has become a hot item thanks to some clever pseudoscientific promotional lingo. Silver has been shown to have antimicrobial properties, begins the sales pitch, and then goes on to describe how silver is used in water purifiers and is even woven into socks to reduce odour caused by microbes. True enough. But deodourizing socks is a long way from destroying the Ebola virus in the body, which is one of the claims. Colloidal silver can, however, do something. It can cause an irreversible condition known as argyria in which skin colour is permanently altered by deposits of silver.
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