The reason to service a regulator is to maintain it in first class working order. To keep the regulator working the parts that deteriorate with age such as O’rings and the parts that wear with use need to be replaced. It is also an opportunity to inspect all the parts for damage. The picture below shows where the chrome has disappeared, this is probably due to the regulator being left with water inside.
Cleaning is also important in this process. It is the opportunity to remove foreign particles that may have entered the valve. Removing all the old grease so that new can be used. Also all the limescale that inevitably builds up can be removed. The photograph below shows limescale build up from just over a years use.
Cleaning is best done in an ultrasonic bath. Limescale is removed with acid. You can use vinegar but other acids are preferable. e.g. citric acid. Better still are the cleaners specifically designed for this purpose. The parts should only be left in the bath long enough to remove the limescale. Leave the parts too long and the metal will become damaged. If the brass parts become pink in colour they have definitely been in too long.
Oxygen cleaning involves the removal of hydrocarbons from the parts. Again this is done in an ultrasonic tank with a specialist cleaning solution. I use Metaclean. A good tip with an ultrasonic bath is to use a container within the main bath. It saves on expensive chemicals and the solution can be made deeper than the main bath to totally immerse the part. The ultrasonic waves pass straight through the container and into the liquid inside. Once again rinse in freshwater after cleaning.
The last stage is to dry the parts. This is best done having done the last rinse in fairly hot water and then using an air gun to remove the excess water. With all this done you have a set of shiny parts ready for reassembly.