I read this on the shave den after a quick web search: (I think I'm going to try it after I acquire some menthol crystals)
How to Make Iced Arko Shaving Soap
You will need about 15 minutes of spare time and the following items:
Instructions
Put your Arko shave stick in the fridge for a while and let it get nice and cold. This will make it easier to grate.
Grate the cold Arko shaving stick into a small bowl. The cold stick will be about as hard as candle wax and will be easy to grate.
Fill a small shot glass with about 1 ounce of hot water. Don't use boiling water, it is too hot. The grated soap will have no trouble absorbing one ounce of water.
Stir some menthol crystals into the hot water. The crystals should dissolve in less than one minute. I used about 2/3 of a teaspoon of crystals.
I think for the first attempt, you should probably not exceed one level teaspoon.
Pour the menthol water into the bowl and start off by squeezing the grated soap into a ball. Once you have it in a ball shape, begin to knead the ball for a minute or two.
Press the ball of soap into one of your favorite containers.