old-fashioned entrepreneur

The other day I was home during the day - unusual for a weekday. Contractors were working on the house across the street. I heard a ringing bell, similar to what I've heard on ice cream pushcarts. A short time later I heard it again. It was an old timer with a pushcart, but no ice cream. He had a pedal-powered grinding wheel to sharpen tools and knives and was making the rounds, offering his services to contractors working in the neighborhood. Now that's the ultimate green small business: keeping tools useable longer and doing it in a way that generates no pollution and gives him exercise in the process.