you can probably clean/repair the one you have if you're careful and clean about it.
I've probably written up the procedure on here before, but basically you need to use an exacto knife or similar implement and carefully cut around the "head" of those four white circles on the back of the switch. Just remove enough material to remove the back plate by sliding it backwards. the point is to leave enough of a nub on there so you can re-melt a new "head" on it later.
unsolder it from the board, and carefully lay all the parts out on a large clean surface.
the big deal here is to document every pieces' orientation exactly. and i mean exactly.
then you just clean all the parts with contact cleaner (i also apply a product like CAIG Pro Gold) and gently bend the fingers out a little bit so they make good contact when you put it all back together again.
use a hot nail or something similar to re-melt the white plastic into a flat disc that will hold the back plate in place.
LC