I pass up a penny nearly every day.
During the past year I have been doing a lot of walking outside in my neighborhood. One one of my routes there is a bronze Lincoln cent in the street, now very well worn from being run over by cars and trucks. It is pounded firmly into the blacktop pavement. It is one coin I can't pick up. My walks over the past year have not yielded much in the way of change, probably no more than 80 cents in total. Paper money is another story. I found a one dollar bill during the summer and found a ten dollar bill just last week.