This would have been the perfect on-the-go litter receptacle, back in 1964, before the redesign of modern car radios rendered its usage obsolete. It was not uncommon, back in the day, to have your litter bag hanging from one radio knob, and your air freshener hanging from the other.
This vintage super-stylish AM car radio probably sported both, at one time or another:
Odd Yard Sale Finds 