Posted 06/14/2011 09:10 am
1982 was the first year of the cupro nickel alloy here. Prior to that nickels were made of nickel. These alloys are susceptible to colour changes from environmental factors besides just plain old fashioned oxidization. Mild heat alone can cause toning in them for example. If the alloy is incorrect and features more copper or impurities other than what is expected, then this toning situation is further exacerbated. Basically, it's not uncommon.
