Any tips for antiqued metal materials?

There are a lot of renderings of antiqued coins in my future. Likely thousands. Does anyone have any tips for setting up a material that does at least some of the antiquing automatically? It’d be pretty cool to avoid texturing each one by hand if I can!

My knowledge of procedural materials is pretty basic, so any and all tips are very welcome!

Example picture for reference.

What do y’all think?

Have you looked at the new Chaos materials (TriplanarTex)? Here is a quick Google search for old metal

v-ray dirt. if the coin surfaces are geometry/displaced.