A little history about Shaving mugs:
Shaving scuttles and shaving mugs were developed around the 19th century; the first patent for a shaving mug is dated 1867. As hot water was not common in many households, one way to provide hot lather was to use a scuttle or mug. Shaving mugs often look like a standard mug, however, some also have a built in brush rest, so the brush does not sit in lather. Modern versions of the scuttle are in limited production, usually by independent potters working in small volumes.