First, you drop a drop of water on the leather to see if the place with water will turn black slowly. If it turns black, it means that leather absorbs water quickly. Our professional name is aniline leather. If you want to clean this kind of leather, you can buy anhydrous alcohol. Remember that it must be anhydrous alcohol, which is sold in general chemical stores. Then rub a sponge or cloth that won't shed hair in the dirty place of the leather coat to see if it will fade before rubbing. If you don't want to do this, you can also add a shampoo and a conditioner together, then put them in a bucket and wash the whole leather coat together, but after washing, you should tidy up the shape of the leather coat and hang it professionally with a big hanger. No matter how you reshape it, the final shape will not be as good as before, of course, you have to spin it dry.
If the leather coat can't absorb water, you can directly adjust the warm water with shampoo, lay it flat on the table with a cloth that won't fade, and dry it with another dry cloth when the friction moisture on the leather coat is extremely high. Wipe where there is skin, but don't wipe where there is no skin.