During the use of the watch, the lubricating oil on each part of the movement will gradually evaporate and dry up with the passage of time, and the friction between gears will produce some metal chips, which will increase the resistance when rotating. At the same time, no matter how well the watch is sealed, over time, some tiny dust and water vapor will invade the movement from the gap of the case and form dirt. Therefore, after the watch is used for a period of time, it is necessary to disassemble the movement components for cleaning and add lubricating oil. Oil washing and maintenance of watches is very important after-sales work, generally 2-5 years, while Rolex needs to wash oil every 5-7 years. In addition, while checking the movement faults, adjusting and repairing parts, the oil washing of the watch movement must also be carried out when problems are found, because the movement will produce impurity dust and enter the sealed movement after maintenance, so it is very necessary to carry out the oil washing procedure. The purpose of oil washing is to keep the watch parts clean and necessary lubrication, so as to ensure the accuracy of the watch parts, improve the travel accuracy of the watch and prolong the service life of the watch.