I have obtained an old mirror that needs restoration. Its design suggests to me it may be from the 1950s and there is a French-language label on the back side, so maybe its provenance is French as well. (It is almost certainly European.) There are four metals springs at the back corners that fix the mirror (its wooden back side) into the metal frame.
I am wondering this: How can I remove (or unfasten those springs) in such a way that I can temporarily remove the mirror from its frame, clean the (rusty) springs, and put everything back together again? For instance, are such springs kept in their fixation holes also by spring forces and could I pull them out there without damaging the hole?