They are an excellent cleaning tool, properly adjust. As provided you could purchase different cleaning pads. Most pads could be cleaned and used over, kind of a scotchbrite abrasive pad. IMO these pads could be fabricated. There are (4) push-pins that attach the cleaning pad to the car. Once over the main lines of your layout before use, easily cleaned dust and some traction tire residue that could be troublesome.
Additional information added 2/4/13.
There were two different types of pads. The abrasive pad, mentioned, and a soft felt pad. I have spares of both.
Instructions as follow:
Instructions on Adjusting Pad Pressure.
(1.) Press down on short articulating bar just behind adjusting wheel.
(2.) Turn nylon wheel clockwise to decrease pressure and counter clockwise to increase pressure.
(3.) Use the red index line to count the number of turns in either direction. Repeat the process at opposite end of the unit for a uniform pressure across the pad block.
(4.) If block gets out of level adjustment, place unit on flat surface and adjust until block is horizontal to surface.
PAD REPLACEMENT
(5.) Remove the nylon plugs that hold the pad in place by grasping the pad (end edge) at the plug(s) and pulling away from the block. This will loosen the plug enough to allow you to remove the plug by grasping it with your finger (nails) and pulling it out of the block. Pads can be used on both sides.
(6.) To install new pad push plugs into the pad and push plug into hole in the block.
I always had better luck pushing it. It worked well with my Atlas track that has a flat top profile.