I was wondering if some rc'ers knew how long it generally takes for a silver coin to 'tone'. I am not talking about those crazy rainbow specimens but just your average toning. I dont think its entirely dependent on date but defintely part of it. I even heard of a method to articifically tone to create that 'crazy rainbow' effect, which is a travesty in my mind

But at any rate, in theory, I suppose any coin that is around for long enough will tone, if not cleaned, or is this wrong

Like I was wondering if left untouched how long would a 2011 BU SAE take to tone, in say your average moderate climate. Airtight or just left out to be exposed to the 'elements'.
Any ideas??
Thanks!