What are these, tire valves? (New pictures added)

[SkyPirate]

I found these all in the same hole today. I am guessing they are tire valves with the rubber disintegrated. What do you think?

[Sheldon J]

Kinda big for tire valves....

[NOLA_Ken]

parts of early spark plugs?

[Silver Searcher]

I have been in the tyre trade for over 35years, and have never seen tyre valves like that

SS

[Mich. Wolverine]

They look like tighteners that are on the outside of a banjo.

Wolverine.

[SkyPirate]

I found these all in the same hole today. I am guessing they are tire valves with the rubber disintegrated. What do you think?

I emailed a person who sells antique banjo parts today and asked him if these were part of a banjo. Here is his reply:
"Yes, they appear to be banjo tuners....missing the buttons.
These were used commonly on old 5 string banjos at and before the turn of the century.
Hope that helps.
Steve"
The picture is of a similar tuner. Thanks for all the help!