The reason why washing wool trousers is not recommended is that wool may shrink, fade or deform after it is introduced, and the more high-grade wool clothes shrink more seriously. It's ok if you have to wash clothes, but the shaping and ironing after washing clothes are the key. One of the topics of the 4th National Professional Skills Competition for Dyeing and Washing Industry is "Clothing Ironing-Players ironing wool suits and trousers for 30 minutes". It can be seen that it must be ironed, otherwise it will not blind the good woolen clothes.