Rachel emailed in the following tip:
Your recent guest post about how to make liquid laundry soap without grating the soap got me thinking. I make my own laundry soap but I prefer to make the dry version. I use Ivory soap bars — and I really despise the grating part.
Anyway, I recently did the “microwave a bar of ivory soap” experiment with my daughter. After you microwave it, it is very crumbly. I microwaved a bar today, put it in a zip-top bag and crumbled it easily with my fingers. The pieces were small, but not as fine as I like them. I then used my rolling pin on the bag as if I were rolling dough. That turned it into a fine powder!
The whole process (including the microwave part) took less than ten minutes. My fingers are not sore from grating nor did I lose any skin! Score!!