Shaving Made Easy/Chapter 10
The shaving cup should be of earthen ware or china, and large enough to accommodate the ordinary round cake of shaving soap. Some cups are made with two compartments, one for soap and the other for water, but this arrangement is unnecessary, and in fact, not so convenient as the ordinary cup, for it leaves too little room for making the lather.
If possible, the cake of soap should entirely fill the bottom of the cup so that no space is left between the soap and the sides; otherwise water will get in and keep the bottom of the cake continually soaked. If it is found that the cake does not quite fill the space, take the soap out and warm it until it becomes somewhat soft, then put it back in the cup, and with the hand press down the sides all around, thus flattening out the cake until it quite fills the intervening space. If at any time the soap should cleave away from the sides of the cup, it should be pressed back as at first. This will be found the most convenient way of using the soap.
Great care should be taken to keep the cup scrupulously clean, rinsing it out thoroughly each time after shaving, in order to remove any lather that may have been left unused. Keep the cup away from dust.
Some use the sticks of shaving soap and make the lather on the face. While this is permissable, we think the better way is to make the lather in the cup and put it on with the brush.