I use a center line track cleaning car with goo gone. I also have three hart gondolas that I have added Masonite scrubbing pads to, following an ancient practice that was either invented of popularized by John Allen. I usually put a Rivarossi Heisler (a geared locomotive for those who have not encountered such beasts) on either end of the center line track cleaning car. I put two of the heart gondolas on one end of the train, and one on the other.
With this set up, running the train across a section of track back and forth twice (four passes total) will clean most normal sections of track.
On almost all of my cars I have replaced any wheel sets with plastic wheels with Jay Bee wheel sets, which are blackened brass I have been using some Proto 2000 wheel sets as well. brass wheel s don't collect dirt, and may help clean track with frequent use. Plastic wheels will play catch and release with dirt spreading it around. Once a long time ago I used a lot of KD wheel sets. I loved them, as they looked really good, were non magnetic ( important if you use magnetic uncoupling which is really cool), and had very good rolling characteristics. I found over time that the aluminum ( I think) that is used for the wheels attracts dirt , and can be very difficult to clean, so all my KD wheel sets have been replaced. A side advantage to metal whees is improved tracking due to the extra weight below the center of gravity, and the sound of the metal wheel sets rolling through switches and rail joints is nice.
I have made jumper cables to clean locomotive wheels , I put them up side down in a homemade foam cradle, hook up jumper cables so they will run, and run them upside down. doing this I can easily clean the drive wheels with rubbing alcohol on Q tips. Leading, trailing and tender trucks I clean with a brush attachment on a dremil, making sure to keep the speed way down to avoid removing material from the wheel tread or melting the bearing surface.
I have a block of rubber like material, with some very fine abrasive, that I got from Micro mark. that I will use on stubborn dirt. it's action is similar to a bright boy, but the grit is much smaller
I will try to post some pictures of my techniques.
Bill Nelson