I know I'm late to the party on this one, but my personal thoughts, with 800+ sections myself:
- if the track is so rusted that some quick passes with maroon scotchbrite (for metal work) won't clean it up - FUHGETABOUTIT. Used O/027 track is way too cheap and plentiful to spend much time cleaning it up, unless there's some particular sentimental reason for it. Evaporust does work for rusty stuff, but you gotta be careful and not lose track (pun intended) of time - soaked some old wrenches and sockets for too long (got sidetracked and forgot 'em) and now they look and feel like absolute crap and don't want to clean up.
My preferred method:
- quick visual inspection to separate the usable from the twisted/trashed/rusted
- get a jug of Greased Lightning, mix w/ water at prescribed ratio in a large tub
- dump in a pile of track to soak for a short time
- quick scrub w/ brush of your prefered comfort/style to remove grease/grime
- thoroughly rinse off, and thoroughly dry (I used a separate room with a wall heater cranked up, or the oven up just enough to warm should work)
- a quick continuity check to ensure the center rail is still isolated
- get a box or few of 3M Scotchbrite maroon pads 07447 from Amazon (cheapest) or your local parts store (pay throught the nose). They call this the "general purpose" pad but I remember it as the metal/brightwork pad. If less than a minute of quick passes with this pad (wearing gloves) doesn't give you a dressed up rail top/upper side, then your tolerance for rust at the beginning visual inspection step is far greater than mine...
That's my nickle's worth, your mileage may vary...