First of all, washable down jackets can't be washed, which will cause the fillers in the down jackets to stick together and damage the clothes. Secondly, if the parts are dirty, clean them. First, wet the polluted place with warm water with a soft brush or towel. Then spray a little detergent on the dirty place of the down jacket and brush it with a soft brush or towel. Finally, put it in a ventilated place to dry, and be careful not to expose it to the sun.