I clean tracks about once a year ( sometimes more ).
For the 3 tunnels ( and remote areas ) on my layout I use my R&R Lines track cleaning car.... which has 2 rollers ( uses small paint roller pads ) I mean I could clean the tunnel tracks by hand using the access areas, but its easier to use the track cleaning car ... which I must say is pretty effective. I put Goo Gone on the padded rollers and run the car... making one pass through the tunnel, behind a switcher locomotive. I then replace the wet Goo Gone rollers with dry rollers and run the car ... again through the tunnel ... this time being pushed ahead of the locomotive. After doing this the goo is usually gone
The rest of the tracks which are in easy reach ( or not ) I use Goo Gone on a rag then wipe off with a clean cloth.
I do clean off pick up rollers on my locomotives regularly at all lubrication sessions. I do lubricate engines regularly and keep a detailed log of the the maintainence work.
performed. I also clean locomotive wheels when I lube the locomotive. Aside from passenger car rollers I rarely ever clean wheels of rolling stock.