Having used those for their intended purpose, I can say they're pretty nasty and would be hard to remove from a confined space, since they have a pasty consistency...    

I prefer to use DeOxit.  The stuff is marketed like snake oil, and is expensive, but I've been using it for close to 20 years and it really works!  On low-signal / high impedance circuits, you want to be careful, since it is conductive.  For example, cleaning the fine gold contacts on my 7000-series Tek oscilloscope plugins, I use a small strip of paper moistened with DeOxit.  IMO, the spray is like using a fire hose to water your lawn, so, I prefer to buy a small vial of the liquid.  The 7.4 ml vial will last you a lifetime...  It has saved my bacon on countless occaisons.  

Keith