I don't use abrasive cleaners, anymore. The Bright Boy always made the trains sound crunchy, after I used it, and they still didn't run that great. If the tracks are really dirty, like they were last week after four or five years of no running, I use Maas metal polish. (I know, polish is technically an abrasive) I use it as sparingly as possible, and wipe off any excess, afterwards. Things ran great after that, but the wheels seemed to get dirty again fairly quick. After that, the liquid cleaner on a piece of soft scrap fabric (old T-shirt, in this case) seems to work well for me. I pull the fabric over a small block of wood.
I had been putting the cleaner directly on the wood, but that was still giving me problems running.