Metal Syringe I Have An Antique Glass Syringe With A Stuck Plunger.?

I have an antique glass syringe with a stuck plunger.? - metal syringe

I am being the time of the piston of a little antique restoration glass syringe (without needle) with a metal seems to stagnate. This is a collector of old medical instruments. Has anyone suggestions how to remove something?