Being a tight blighter I like to use old track. You know Hornby tin plate, Triang plastic base etc. However the big problem is the connection between track lengths. Physical cleaning can be problematic. There are special cleaning potions for sale and which seem to be in the top scent price range (this I know from buying SWMBO's christmas gift). Has anyone discovered a more common and readily available cleaning product that does the job. As such track often needs a good clean full immersion is not a problem. 
I have not yet tried shorting the track across the mains! not so dangerous with modern circuit breakers.

Any suggestions appreciated ( even if the mains trick works or not ).

Happy New year

David

By far the best cleaner I've come across is IPA David.

Definitely not for full immersion because that would prove expensive but it really does shift tarnish and dirt well.  Buy it online - it will come via courrier because it can't be posted - but, whilst dearer than Fairy Liquid, it's not that expensive ……………………..

 Rust on steel track is a different matter and IMHO, you'd be far better off binning the stuff that attempting to clean it.  There is surely a limit to what one is prepared to do to save a few coppers ………………….. :hmm