The author of Instructables under the nickname nabind tells how he artificially aged a relatively modern wall clock.
Finalization of the watch begins with the master dismantling it. Stop, not until the last screw! The mechanism must be left assembled. Unless, of course, you are a watchmaker.
The master removes all the paint (or all varnish) from the watch case with sandpaper 60 or 80 grit. When the coating does not exactly remain anywhere, it processes it with sandpaper at 120, then at 220 grit. After that, it removes all the resulting dust. Completely. It is necessary that there is not a single speck of dust left.
It paints the watch case in two or three layers, allowing each previous layer to completely harden before applying the following:
From the glass in front of the pendulum, the master removes the word REGULATOR with a knife. Through a makeshift stencil, the letter B is mirrored on the back of the glass with a paint imitating frost. Glass may have sharp edges, so take it only with gloves.
The dye, originally intended for dyeing leather products, is used by the master for other purposes - it makes the dial old:
Collects the clock and returns it to the wall. Now they look much better.
Of course, at the auction, bulletin board, flea market, etc. it is impossible to give out such watches as really vintage. However, close and so it is clear that they are quite modern. But to indicate that they are artificially aged by a qualified master is possible and necessary.