I recently fixed up a steel bike for someone special. The pedals needed grease, the bars needed adjustment and tightening, and it was rusted as heck. Pedals and bars are easy; tighten this or apply lube to that. The rust was another problem. At ABR we have these steel wire brushes that we use. These were okay for getting the grimy rust off, but they never got the surface rust, and you can forget about getting the nice chrome or steel look back.
So I did some research and I came across this video on youtube which seemed like magic.
For all you science minded people, since the rust (iron oxide) is less dense than the aluminum and the steel is more dense than the aluminum the aluminum takes off the rust without damaging the steel.
So get a cup of water and a rag, dip some aluminum foil in it, and rub away. It is like magic.
Albany Bicycle Coalition 