cleaning old track

Sand paper works great

If it's very rusty, first soak with Evaporust fora day or two.

If it just needs a basic cleaning, try this -

I think the only balanced answer is, "It depends."

IOW, if the track is generally good condition, IMHO a light touch is in order -- Scotch-brite or similar low-abrasion pads should do just fine to remove surface dirt and light oxidation (and for later maintenance). At the other end of the spectrum, if there is heavy rust, using a chemical rust remover might be in order (I've used half-and-half vinegar and water to cover the rusty track, heated in the oven and then rinsed in baking soda and water to neutralize the acid and finally dried carefully, with some success on moderately rusted track -- be aware it may also remove some or all of the paint from the ties!), and as a last resort, you can use sanding blocks or fine emery cloth to remove heavier rust, or rust not fully removed by the chemical methods. In any event (and *especially* if you use abrasive cleaners, which can remove the "tin" plating from the steel rails), finish with a final thin coat off No-OX or similar sealer to inhibit future corrosion.

BTW, don't overlook the connecting pins! I'd suggest removing all the pins, buff both ends of each pin with a wire wheel, clean the inside of the rail ends with a small rattail file, and reinsert and crimp the pins in place (track pliers are helpful, but plain or needle-nose pliers will do for a pinch ).

Oh, and while you're at it, make sure the insulating pads for the center rail are in good condition, and replace any that are showing signs of wear and tear. The final check is to test continuity end-to-end for each rail, and ensure that the center rail is completely insulated from the side rails and metal ties. You can temporarily connect several sections of track and test them as a block to speed the process -- any anomalies indicated can be traced back to a particular section by the process of elimination.

In any event, good luck!

Once you have removed any loose crud, it becomes a “while you’re waiting” project. You can keep a bag of track and cleaning supplies pliers wherever you normally have waiting time. It’s tedious but easy, so you can farm it out to kids old enough to get the idea or do it yourself while you’re out railfanning and nothing’s due for a while.

If you decide to wash the track, do it before you put the pins back. If possible, take advantage of summer sunshine to get the clean track good and hot so you know you’re not trapping water in it.