Is it just dirty/dusty or is there oxidation or something else going on? What type of material is it? I’d start with a damp cloth. Or just replace the trim if there’s some permanent change to the material.

Honestly, looks like they need a bath in EvapoRust.

The trim on the backglass is the tricky one that can be difficult to remove without damaging the artwork or chipping the galss edge.

I put a piece of this adhesive chrome tape on mine. Needs a bit of a trim with a razor blade but looks great to me.

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