Robin banks from the 60’s.
And here are the Batman banks.
These were produced in mass quantities by a Japaneses company called Lego — not “that” Lego. If you clean them too aggressively, the paint can flake off, which is what I think happened to the white banks I have. Those might be unpainted from the factory, or they might just have had a thorough scrubbing, I’m not sure.
These banks are easy to find on eBay, but finding them in good condition can be a challenge. The Robin bank is definitely harder to find and, for some reason, most of the ones I see have had their head broken off and reglued.