Over a year ago I got this antique porcelin shaving mug, but only recently started using it (I had to use up my other soap first). Most mugs I've seen have a single bowl you put soap in and lather from.
What is pretty unique about this mug is that it has a lower bowl you can fill with hot water and soak your brush, and an upper bowl for your shaving soap. Before this, I had been soaking my brush in a separate container.
@AugustusMorning I wash the brush out and shake it out before I put it back in the bottom. If you mean the top, I won't know for a year or so when I use up this soap I guess. I try to leave suds on the soap itself as it just becomes more soap I can lather next time.