Posted 01/10/2011 08:28 am
"Carbon spots" are, as you surmise, not literally carbon. They're called that because of the colour; they're actually the usual sulfide-oxide mixture that cause shiny copper to tone dark. It can't be "fixed" by any means that wouldn't be considered "cleaning" in all the wrong senses of that word.
Carbon spots are usually caused by somebody talking, coughing, sneezing or otherwise expectorating in the general direction of their coins. The sulfur-based enzymes in saliva cause the reaction to proceed faster than ordinary water drops would.
There's no cure, but there is prevention. If you do accidentally get saliva on your coins by the aforementioned means, wash it off with distilled/deionized water straight away, before the spots appear.
Carbon spots are usually caused by somebody talking, coughing, sneezing or otherwise expectorating in the general direction of their coins. The sulfur-based enzymes in saliva cause the reaction to proceed faster than ordinary water drops would.
There's no cure, but there is prevention. If you do accidentally get saliva on your coins by the aforementioned means, wash it off with distilled/deionized water straight away, before the spots appear.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
An edge view would appear squashed. 4500:1 ROI if that thing sells. 
