For example, if the customer doesn't understand and asks you to dry clean it, in fact, his clothes are suitable for washing, so you can help him wash them. It makes no difference anyway. The effect is not necessarily worse than dry cleaning, which is immoral. You asked.

If it doesn't wash off, it's not good. It will damage clothes, especially wool.

How to master it is up to you.

Actually, it can be mastered. Generally speaking, what to wash and dry clean is common sense ~ for example, wool must be dry cleaned!