✅ SOLVED Pulled from the Gulf part I

[Crispin]

non magnetic, doesn't react with acid, reduces with aluminum and baking soda. Jet black when I pulled it up.

 

[SkaBa]

Valve stem cover.

 

[BosnMate]

End off a grease gun. End of the hose fitting on a hand pump grease gun, the part that fits on the zerk fitting when greasing machinery.

 

[ARC]

My guess... Air conditioning Freon hose screw on end.
Or...
End of an older style screw on air pump hose.

But am leaning more toward the first.

 

[comfortably numb]

Female end to a quick disconnect for an air hose. They are usually brass.

 

[Crispin]

Brass would make a lot of sense.