nickel cleaner

[Ochaye]

what do you guys use for tarnished pups?

[Fourth Feline]

A dab of 'Carr & Day & Martin' brand liquid silver polish. It was the only brand in the supermarket ( at the time ) that did not carry a warning advising  against use on nickel . Has worked fine on mine.  :)

[impossible]

All with a nice cotton cloth (AKA ripped-up old T shirt):

Hot breath and elbow grease

Ordinary guitar polish e.g. Trick or Dunlop 65-type stuff.

Finish buffing compound (fine liquid stuff for hand-polishing as opposed to coarse buffing wheel stuff)

Metal polish, preferably fine, Silvo/Brasso if it comes to it. That's a bit too abrasive IMO.

Start out mild and work up depending on how bad the buildup of crud is. Nickel covers do tend to fade with age, sadly and no amount of polishing will put that newly-plated shine back. You can even make it worse as polishing can take off small amounts of the already very thin plating.