How does contact cleaner work?
Audio switches and sliders have a problem with oxidation of their contact surfaces that higher voltage switches do not have. The usual solution to the problem is to give the audio contact surfaces a gold or other exotic metal coating, but that is expensive, so it might be too thin and wear out, or not even be there.

There are products to remove the oxidation and protect the surface from further oxidation. The one I use is DeoxIT. 

You can also just exercise the pot, run it rapidly up and down a few times, I've seen that done and work.

For other solvent type cleaning operations (for instance, say, the contacts are in a midi accordion that has spent too much time in greasy bars), be very careful of things like rubbing alcohol or most solvents you can buy at the hardware store. Almost all of them have been denatured with some sort of glop. If you are bent on using a particular solvent, put some in a glass dish and let it evaporate, to see what is left behind. The only no-residue solvent I have found so far is Ronsen Lighter fluid.  

Of course, aggressive solvent use is a touchy thing. Do not get it anywhere it does not belong.