Midcentury Collier's Encyclopedia Advertising Calendar Bank

A midcentury Collier's Encyclopedia Advertising Bank. The circa 1950's plastic and metal coin bank features advertising on the front and a "conscience slot" on the reverse. No key. I have no idea how the calendar works or if it still works! The advertising piece measures approximately 4 3/8" x 3 1/2" x 1 1/2" and is in good vintage cosmetic condition.