I've tried it a few times with mixed results. If it's not done right, the shredded pieces never some together, and end up falling out as you lather..... but curious why you bring this up here? The tonsorial pucks are hard-ish, but they can be pressed into a tub. I took my tonsorial puck and pressed it into an empty CBL tub. Work great..... (not grate)!Have any of you tried grating hard soaps into a bowl? I've seen it done here from time to time.