What does this sentence mean, people lose things, but they clear their bones?

It means that people can be free and easy as long as they let go of secular desires. When human affairs are lost, it means that there are many complicated emotions in the world, and people are bound by this emotion. That clear bone implies that if you let go of worldly desires, people will be detached and free. Therefore, when people's affairs are lost, there will be a clear skeleton, that is to say, as long as people let go of secular desires, they can be detached and free.