Pick up Faucet Brite and BrassTech online, and see which works better for you. Recommended by manufacturer.

My nickel faucet manufacturer recommended these two products:

Flitz Facet Wax+ (seems like a very "eco" product made with Carnuba and Beeswax)

LE SX de Gagnon's SX

I purchases both on amazon.com. They both seem to put a thin coat on the nickel to keep it from spotting. I prefer the FLITZ.

I haven't had much trouble with spotting on my polished nickel fixtures, installed now for about 10 months.

For regular cleaning/maintenance, I either use water and a cloth, or Seventh Generation bathroom cleaner. For the once or twice a year polishing, the stuff in the red tube at William Sonoma. What is that? Wenol I think....

Flitz is what we've used for years. Keeps them perfect.

A wax will not remove the tarnishing that is already there, however.

Many products combine a polish and a wax.