Caring for vintage handcuffs

I just recently purchased handcuffs from the Radner Houdini Auction. The locking mechanism still works but you can tell one of them is harder to open than the other. Should I use oil of some sort to keep them in good working condition? Im thinking of having them mounted in a plexi case. Any suggestions...or slaps on the wrist are welcome.

Thanks,
Francisco

That's fine.