From my experience, very few customers even knew what they were. Once or twice a customer was getting out change and found, say, a wheat penny and decided to keep it. I usually swapped out the change as soon as I could and put the old coins in the small pocket on the right side of a pair of jeans.
It pays in the end to be on the up and up too. This afternoon I went into a credit union and bought up all their excess nickels and dimes, the total the teller added up came to $426, but I got home and did my own count and came up with $436 - I called her right away and let her know the $10 will be there in the morning. What comes around goes around and when tellers have made mistakes in the past and I have corrected them - they remember you when they get goodies in that you might want since you saved them from being off in their ledgers.