Traditionally, ceramic cups are used. Something that is deep and wide so you can work up a good lather with a brush.
The trick in making shaving soap isn't really the cup ... rather the soap. You need a soap that has abundant lather that lasts a long time. Nothing is worse to a brush shaver than having the lather break down.
You know coconut and palm kernel makes abundant lather ... how ever, it breaks down. The best thing I've found to sustain the lather is stearic acid. Use it with caution ... a little goes a long way and it causes acceleration in your soap batch.
The trick in making shaving soap isn't really the cup ... rather the soap. You need a soap that has abundant lather that lasts a long time. Nothing is worse to a brush shaver than having the lather break down.
You know coconut and palm kernel makes abundant lather ... how ever, it breaks down. The best thing I've found to sustain the lather is stearic acid. Use it with caution ... a little goes a long way and it causes acceleration in your soap batch.