Bell braziers
People usually find weird objects in new apartments that were left behind by the previous tenant. Most of the times, it’s the odd article of clothing, but the most exciting stuff is money or gold. This, however, was neither. It appeared to be a metal serving dish with a latch and lid.
This is actually a bell brazier. These were used in the olden days to provide heating to specific rooms in a home without a fireplace. It works by tossing an iron ball into your furnace, waiting until it heats up, then placing the ball inside of this bell brazier.