I like to buy less than perfect O scale trains and fix them up. I'm cheap but I also enjoy bringing something back to usable state. This past week I got a MTH offset cupola caboose that had gotten wet and was broken up pretty good. The truck sideframes were bent out at a 45 degree angle, one axle was missing and the 3 remaining had rust and that white 'crust' forming on them.
I found a Dremel tool kit, I had been given a while back, that had what was called abrasive wheel. I bolted it into my Dremel and after I had rebuilt and oiled the trucks decided to try it out. I ran the Dremel at MED speed and held it against the wheels at a slight angle. This caused the wheel to spin but also allowed the abrasive wheel to clean. After just a few minutes the wheels looked good as new! After I cleaned the wheels I rubbed them with a rag with just a trace of oil. You could never tell they were covered in rust and white crud!! This is the wheel.....thx