Parts Only Honeywell Chronotherm III Programable Thermostat Used

Used Honeywell thermostat! * Chronotherm III * For parts only * Door is off - am including it * According to my HVAC guy, there is corrosion in the connectors (right above "alkaline batteries only" - did not try and clean * When it was on the wall, it did turn on with the batteries but did not operate the furnace * Comes from pet-friendly home