The fine hardware I have used for hanging of screens is so old that they are probably almost vintage modern. Three pieces were saved - to my great luck - in my father's rich hardware depot. Their origin is lost in the mists of time, but now they have new life on board with us.
First, however, a bit of old corrosion needed to be eliminated.
My best tip for this consists in first giving the object an acid bath, for example, in half acid/half water (really hot, so it goes faster). Do not leave them too long - just until bubble formation ends.
Then it is on to Brasso and elbow grease, though rarely is much of this needed after a tour of the acid.
The result you can see below.
Before and after the acid bath but before polishing
Could it be any easier?
Once polishing with Brasso and you would almost think they came directly from the manufacturer
[Ed. note #1: Remember, when diluting acid, always add acid to water (A comes before W is the mnemonic to remember this). Never add water to acid! If you do, the heat released will be enough to boil the water and you will be spattered with a boiling acid mixture.]
[Ed. note #2: Always wear safety glasses when handling acid.]
[Ed. note #3: Apologies for my poor editing of Google Translate's translation from the original Danish.]