It's not really oiled, it's covered with sequins. If you don't wash it, the bright film will seal the dirty things inside, and it will be moldy when it is wet.

Leather clothes are cleaned with detergent prepared from Jialijia leather imitation oil. After cleaning, leather clothes are maintained with simulated oil of Jialijia leather. Leather clothing is soft, natural, beautiful, durable and mildew-proof.

Specifically, you can search Baidu's website: Basic Principles of Leather Maintenance, or go to the homepage of the professional website of Guangdong Leather Association to read the training materials: Identify the advantages and disadvantages of leather care agents.