Walthers makes a cleaning block called a "Bright Boy", which does about the same job as the suede block. Many folks say not to use any abrasive cleaners since they can leave tiny scratches in the rail head that can attract more dirt. They use some form of electronic contact cleaner with a cloth or paper towel to remove the dirt and oxidation. There is a rolling track cleaner out there where you wrap the brass slug with paper towel, soak it with cleaner and push it around the layout. Oxidation of the rail is more of a problem with brass track. Not so much with nickle silver. Stay away from steel - it rusts.