There is no problem using ScotchBrite pads on Gilbert track. It is an unplated steel alloy so the rails will not be damaged.
The GarGraves rail is formed from slightly thinner steel and the profile is not the same as Gilbert track. GarGraves has a more rounded top. There is no operating difference with PullMor engines but the link coupler engines without PullMor had less traction on grades on my layout.
To keep track clean it is better to clean all the car wheels, not just pickup wheels. A consist with dirty plastic wheels seems to redeposit the dirt on the track. The best way I have to clean all these wheels is to couple in a Centerline track cleaning car for multiple laps around the layout.
