I have original AC Gilbert American Flyer track, all of it over 50 years old and some of it with oxidation. I have used Scotch Brite green pads to remove the rust and liquid track cleaner afterwards to remove residue. Running trains regularly and periodic cleaning with the liquid cleaner seems to be a way to keep track in good shape. A Bright Boy track cleaner also does a good job of removing the rust, but keep in mind that you need to control the humidity in the train room.
As an added note the track cleaner I use is called "Track & Rail Cleaner ACT-6006
Ray