Cleaning the metal face of a Jeff Rowland Model 3


For reference, here is the unit:
https://www.hifi-advice.com/blog/jeff-rowland-company-special__trashed/jeff-rowland-power-amplifiers...
Anyone know how to clean one of these metal faces?  Mine has a couple of splotches.
Also, anyone know if you can replace the faceplate of a Rowland with the newer polished look?

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