my father used to work in a machine shop. the coffee break caterer was a local mom & pop/ out of their kitchen affair. the guy would pull up with his '57 wagon, open the hatch glass, drop the tailgate, and start serving. the doughnuts were on an uncovered bakery tray and the coffee came from a military surplus coffee urn. he'd leave the engine running and the smokey exhaust would curl up under the hatch filling the entire car with smoke. this was about '62 or '63.
to this day, when i smell exhaust i want a doughnut & coffee.