Can platinum coins discolor or show signs of age?

CardsFan

I read in Coinworld where platinum coins will not tarnish or oxidize, and are nearly impervious to acids. What effect can acidic gases have? Will these coins show any signs of aging even if they are improperly stored?
thanks

Conder101

Platinum is like gold, basicly impervious to most anything. And other than the russian platinum coinages most all of them are .999 fine so there's no problem with copper spotting. About the worst that can happen is a layer of dust.