After getting some sought-after advice and reading a very good article in Model Railroad Hobbyist about track cleaning, I purchased mineral spirits to clean my track and Wahl clipper oil to topcoat the rails.
Both the mineral spirits and Wahl oil are what’s called non-polar solvents. Non-polar means that the solvent prevents micro-arcing which creates dark powder-like gunk that inhibits good electrical contact. So, between both products, I should be good for excellent operating performance.
Update on rail conductivity: after using the Wahl oil approach for a while I wasn’t happy with the results. Initially, I cleaned the track and applied the oil sparingly, but over time the engine started hesitating quite often. I discovered there was a large buildup of black on the rails which was hampering performance.
After cleaning the track with a cloth multiple times until the black was gone, I decided to apply a thin coat of graphite by quickly rubbing a carpenter’s pencil on the inside of all the rails. The engine now performs flawlessly. Obviously, I’m going to stick with the graphite!