If you have decided to go ahead and clean the movement without stripping it down for attention, and provided that it lies within the categories described earlier, prepare the movement for cleaning.
There are various proprietary brands of cleaning fluid available and these have considerable advantages over home-made mixtures. Some are water soluble concentrates to which you add 7 parts of water to every one of fluid.
Others are oil or spirit based cleaners that are normally used in ultrasonic cleaning machines. Ultrasonic cleaners are tanks of liquid with transducers behind the sides or bottom. These transducers create such high speed vibrations in the fluid that the dirt and contamination is literally knocked out of the pivot holes. They are almost indispensable in a busy workshop, particularly for servicing small alarm clocks and other mechanisms not needing to be stripped.
Avoid inhaling the fumes from any of the cleaning fluids on the market, and always read the labels. Wear safety protection where appropriate, such as chemical resistant gloves and eye protection.
Immerse the movement in the fluid. Any part not immersed will be marked along the fluid line, so be sure to use a container large enough. The time taken to remove the oil, tarnish etc. will depend on the condition of the movement. Check after about 10 minutes. Light brushing will help loosen the grime. A convenient vessel for immersing the movement is a plastic tub with a lid. When the brass is clean and free of grease etc., remove it from the solution and rinse thoroughly in warm water.
It is essential to dry the movement thoroughly to prevent rust forming on the steel. Ensure that no moisture is trapped between the coils of a spring. A hair dryer is one way of drying out the movement, but remember that they are not designed for use in wet environments or with flammable liquids, and there could be a risk of electrocution. When thoroughly dry, refer to the chapter on oiling.
Many clock repairers will decry this section on the grounds that the clock needs to be dismantled and checked. They are right, but if the alternative is the dustbin, then surely this action is justified?
Repairing Your Own Clocks by Mervyn Passmore