Why is it that currency one receives in change from convenience stores is always so nasty? It's crinkly and soft and warm, sometimes sticky. Where do these bills come from? I don't get that kind of well-worn change at the supermarket, or in a restaurant. And at the bank the bills are nice and crisp. It's only at convenience stores that one finds the dregs of currency.
One of these days I may ship one of those nasty one dollar bills off to a lab and see what they can tell me.
In the mean time, I am telling my 7-11 clerks, "Coinage only, please!"