code:

on *:text:!massdevoice*:#: {
  if ($nick isop $chan) || ($nick ishop $chan) {
    var %Devoice.intVoices = $Nick($chan,0,v)
    While (%Devoice.intVoices != 0) { 
      mode $chan -v $nick($chan,%Devoice.intVoices,v)
      dec %Devoice.intVoices 
    }
  }
}