To remove a two month accumulation of dust, either clean by hand with a damp rag, turning it often, or push a track cleaning car like the $25 Bachmann or Walthers boxcars with the floating scrub pad between the trucks.
To remove oxidation (nickel silver oxide is semi-conductive, meaning it hardly passes any electrons through it, but it does pass some), mechanical scrubbing is the best. Some use emery cloth, some use up to 600 grit (I do), some rely alcohol and a cloth, some use a clean steel washer, some use Mother's Mag Wheel polish and then finish off with the washer, some use the tried 'n true Bright Boy....take your pick.
I just purchased a CMX tank car cleaner, all brass, last year and I have run it around my track system exactly once. Then, spring came and I went outdoors. I'm just thinking of going in and taking another stab at cleaning the rails because nothing has moved in my train room, in the garage, in six months. I will wipe by hand first to clear most of the dust, and know for a fact that there's dust. I can see it. Then I'll run the CMX with lacquer thinner (which the latest science says is not the best choice, but that's what CMX recommends, so....).
Apparently, the three best fluids are, in order, kerosene (a bottle can be had in the camping section for wick lamps), then WD-40 Contact Cleaner, then CRC contact cleaner. Their common quality is that they are 'non-polar' fluids, while Wahl's Clipper Oil, ATF, and lacquer thinner are further down the list and more polar in nature.