where are you from ?
the radio shack chain sells "DEOXIT" spray --
but most ALL electrical contact cleaner (any hardware store) works
almost as well
if you are very lucky --
turn the power off -
lay the box on its back --
and try to spray the switches LIGHTLY --to get the liquid inside
if that wont work --send a PM to member 'skippy'
he can tell you how to carefully open it up
so that you can get to the real switch contacts.
good luck - keep us posted -
its a tremendous sounding box