There is actually a department that is only concerned with conservation: CCI.
https://www.canada.ca/en/conservation-institute.html
I am not sure what they are going to tell you, but I am pretty positive that taking a buffing wheel to it will not be the answer. Even silvo and brasso are both frowned on. I know at work the conservators use a special powder. Once the tarnish is treated, wax is often used to prevent deterioration on metal.
If you don't get an answer from CCI, I can put you in touch with our conservator. She will often contact CCI or read up on some of their papers to answer new problems.