Grandfather clocks that have been left for extended periods of time without service may require significant cleaning before they will run correctly and keep time again. In order to properly clean the works of a grandfather clock, you must first open the clock to reveal its internals. If it has been well sealed, there may be very insignificant dust and debris that must be removed. Sometimes, however, the only way to get to the works to clean them is to disassemble the clock from the cabinet.
Things You'll Need
Open the case cabinet on the front of the clock. You will have to remove the pendulum and the weights in order to disassemble it. If you look up inside the case, you will see that the pendulum hangs on a hook. Remove it and unhook the weights from their chains.
Open the front of the clock over the face, and then loosen the bolt holding the clock hands with a nut driver. Set the hands aside where they will not be damaged.
Look on the clock face for screws at its perimeter. Not all clocks have these. If you see screws around the perimeter, then the face can be lifted off of the works. If there are no screws, turn the clock around. The backing plate for the cabinet will have to be removed to access the works.
Unscrew the face of the clock or the backing plate behind the clock. Inside, you will see the clock works. The gears and metal brackets will be connected to the cabinet with screws or with retaining nuts. Remove these fittings carefully, trying not to jar the grandfather clock's works.
Draw the works out of the clock gently. The works can now be cleaned and oiled as necessary to maintain the function of the clock.
Use compressed air to clean any built-up dust or debris off of the gears when they are removed. If there are heavier spots, use a cotton swab dipped in rubbing alcohol.
Never attempt to disassemble the grandfather clock's gears and timing mechanism. These are precisely manufactured. Disassembling the gears will cause permanent damage to the clock that can only be repaired by a professional clock repairer.