Last weekend I repaired two unreliable radio remote controllers with contact spray. One of the remotes was for Nikko RC car and other was for mains outlet remote controlling (bought from Clas Ohlson).
In the Nikko remote has small joystick like controls, but underneath them there was just small cheap buttons on the circuit board. It seemed that some of them did not work as reliably as they should. When I spayed some contact spray to the button, pressed it few times, spayed again, and pressed again type process seemed to make it work much better.
The mains outlet remote controller has designed shape buttons on the front panel, but underneath of them there were those same small cheap buttons on the circuit board. Same process worked also to repair the mains outlet remote controller.
Contact cleaner is a great help in many cases when repairing electronics that does not work reliably. Electrical contact cleaner is a nonconductive, colorless liquid that can be highly flammable if placed near fire or other heated surfaces. So be sure that the contact cleaner has completely dried out before applying power if your electronics device can have parts that can make sparks (power switches, relays) or can become hot. In my cases the voltages and currents on those remote controls were so low that I did not have to worry about fire danger and I could test the circuits while they were still “wet” (the amount of contact cleaner used was also very small).