I recently was given a pair of Marx illuminated switches, and their controller. Pretty sad-looking they were, after evidently having been stored for a great many years. But I determined that they seemed to be just neglected, not abused. And there was practically no rust, just dulling oxidation for the most part.
Testing revealed no shorts, so I set about cleaning them up, which probably took about six hours total, using green scrubbies, brass wire wheel, brass brush, dish liquid, contact cleaner and, of course, WD-40. After a little breaking in, they worked fine, at just 6 volts, on a temporary floor layout that was just dismantled.
I thought, what a testament to the design and choice of materials on this old toy. Pure fun watching the Commodore Vanderbilt run around through them! 
