Whomever doesn't think that Acetone is explosive is dead wrong.
I use 91% to 96% rubbing alcohol from the pharmacy to clean the track. I just dampen a lint free cloth with it, and clean the rails by gripping the rail with the cloth in hand and pulling it around the track by hand. It evaporates in literally seconds. The cloth comes away black with grease etc. An old cotton undershirt works bets. I have been using it on my O gauge track for a year and there is zero rust.
I always unplug the transformer from the wall first, and never have the one pint plastic bottle of alcohol on the train table. I can't imagine how this would be a fire risk.
Maybe the Mr. Clean Magic Eraser works, but I hate them. The Eraser goo that falls off of the eraser as you use it is more trouble to clean up than the original spots, and they stick. Get some of those good strands up inside of a loco or in the trucks or axles and you've got a problem.
Yes, I guess you could vacuum afterwards, but why use anything that you must follow up with a vacuum?