For rare tinplate, I came up with the following to avoid drilling into a family heirloom or pricey collector's item. Using Masonite, I cut myself pads 1 3/8" x 2 1/2" in size. I laid out a center line at 11/16" lengthwise. I added a flexible plastic arm attached by sandwich gluing the pad to the arm with cardboard. I added a small lead weight to the end of the pad away from the arm. Then, at the other end, I sandwich glued two powerful magnets copped from those blinky pins sold at Wal-Mart (they come two to a pin) and placed another set on the car floor. Make sure the pad drags away from the front of the car to avoid snagging scenery and switch points. Heirloom is now safe and track now gets cleaned as evidenced by the pad after ten laps.

A while back I also decided to give my rails a clean, and rubbing them with a cloth usually drew blood when my fingers caught on the bits in turnouts etc... so I decide to make a wooden cleaner to go inside the cloth. My first attempt was a bit big and when combined with the cloth it would not slide along the rail. In a moment of inspiration I removed the cloth and slid the block of wood along the track.. it removed the dirt very well... thus my crud-b-gone track cleaner was born ! I refined the design a bit and now sell them...
see http://crud-b-gone.mixmox.com/

You do need to be able to reach the track to use the cleaner (you should be able to reach all part of your track anyway) so it is not the same sort of cleaner as you have created...