When you say you have cleaned with alcohol, what have you done? Have you sprayed the inside of the switches?
What I do is spray a couple of times inside the switch, then actuate it about 25-30 times while blowing inside it to ensure the alcohol evaporates. Then if it's still sticky, I repeat the process.
You could take the switches apart, but if your board is plate mounted then you would have to desolder the switches in order to do that.