I'm happy to report that the best solution for me is a can of air duster. I used the provided straw and sprayed air to each side of the switch (you feel the air coming through the other side each time). After that, smooth as silk. Should do no harm to the switch as well.
Mine looks something like this but not the same brand:
BTW, I have no idea why this type of spray is so expensive? It's sold in Bangkok for the equivalent of $15-$20. After all, it's just air. Won't complain though.