I like the suggestion of a door knocker. Maybe it could also be the house number?
(I mentioned this thread to my OH who suggested it might be a neuralyzer.
)
I like door knocker as well but I think that’s because we had an antique English door knocker for our last house (I guess it is still packed away) and we have an Irish one for our new house. So, I’m biased.

A fancy house number could be a possibility. I will check out where family members lived in the early 1900s. (Since it was packed with the coin, I think it came from the same decade, but I could be incorrect.)
I had to look up neuralyzer…his reply is similar to what my brother would suggest…same sense of humour. Unfortunately, I don’t have the same quick sense of humour, so I can’t offer a comeback.
Thank you, maddys52