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  for Metal Finishing since 1989
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Carbon monoxide

Someone told me that silver tarnishes because of carbon monoxides-- is that accurate?

K Haugn
- Portland, OR
2002

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No. Silver tarnishes because of hydrogen sulfide ("rotten eggs") gas. The only reason I can think of as to why it was thought that carbon monoxide is responsible is (and this is no way connected with the question)that carbon monoxide is a well known toxic gas (car exhausts and people committing suicide etc), but hydrogen sulfide is even more toxic, The only down side to hydrogen sulfide is that it really stinks and it is doubtful that a potential suicider could stand the smell of the gas! It is claimed you lose the sense of smell at high levels, but I wouldn't want to try it.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2002