“The finish on the MM is a nickle -Teflon coating that has some very desirable qualities. It is conductive, very scratch resistant and very protective of the aluminum body in the presence of salt water or sweat. It does form a thin layer of nickle tarnish over time and exposure to corrosive elements. … We tried 6 tarnish removers and found one that works very well, is readily available, and has been around for more than a hundred years. Other polishes worked but not as easily or well. The tarnish remover is Wright's Silver Polish…”
We now have a bottle in our shop and I must say it brings the transmitters up to an “as-new” quality and has not hampered the transmitters at all.
Remove the belt clip by loosening the grub screw with an Allen key.
Apply a very small (less than a dime) sized amount of polish onto a white rag and buff transmitter. Be careful not to buff the controls panel too much (use some blue tape to cover if you have it.) Follow with another white rag to buff off.