The Dutchess County Board of Elections occupies the building at 47 Cannon St which, if I recall correctly, was a Central Hudson Gas & Electric Company office back in the day.
CHG&E accepted bill payments at all hours through a little slot high on the wall:

A closer look:

It’s solid cast brass, neatly milled, and built to last a thousand years. They don’t make ’em like they used to, probably for good reason.
I’m told somebody once stuffed burning trash through the Arlington branch library’s book return slot. Nowadays, the fire code apparently requires the room behind the slot to be fireproof and isolated from the main structure, which may account for the popularity of outdoor book / media return boxes.