The guide seemed like a fairly knowledgable type who really enjoys his job, so that was nice to see for a change. He didn't even wait for the question to be asked, but volunteered the following:
One of the most frequently asked items they hear about from the public is that people want to know why they continue to produce pennies and nickels at a loss. He said they make up for it with the profits from things like the State Quarters and America The Beautiful Quarters.
I was so tempted to say, "You mean you sell overpriced crap to people who don't know any better and take those profits to offset the losses that you shouldn't have in the first place!" I didn't want to have to leave the tour early...
