Quote Originally Posted by U2Bono269 View Post
I thought of that too, but my concern is that they are irregularly shaped. I'm not sure how I can load up my brush (generic boar) on with some non-stationary bits of soap. I guess I could build the lather in the mug with the soap in it, but I'm pretty bad at that right now.
After you use it once, the soap will probably mush down and, with the help of excess lather, stick to the bottom of the mug. That said, if it doesn't work, you can always wet it and press it down firmly so it does stick, or explore a grating type solution.