Purchased this plaque from a seller when I worked at an antique store in the late 80's. He had four of them (different scenes) but I only bought one and the other three sold in the store. It was not framed to begin with.
The plaque is approx 12" wide by 24 high.
It appears to have been poured/hammered metal but I really have no idea.
I was told (take with a grain of salt) that is was originally part of a series of panels that came from a theater organ in St Louis. Internet searches on the old theater organs has not yielded anything definitive.
When removed from the frame, the metal is fairly thin (1/16" inch) and pliable.
I have never polished or used any kind of cleaner on this.
Would be interested to know what it actually is (if anyone knows) and an approx value of the piece.