The way we use soap bars, getting them all dripping and wet, is inherently wasteful. When soap becomes scarce during the apocalypse, we'll need a more economical way to clean up. This grated soap dispenser looks very promising.
A concept design from Nathalie Stämpfli, the pair of bathroom accessories literally grate the soap into flakes. That way, the bar stays dry in its container, all while you use the flakes to rinse your hands and body into bubbly suds.
Nathalie designed two soap graters: one for fitting over the sink and a standalone one that you can place right next to the bottle of shampoo. With the first, you push the grater and catch the flakes that fall right off with the same hand; with the second, a bulbous dome lets you push the soap to the blade when you turn it in a circular motion.
Granted, this makes for more work than just rubbing the block of soap on your body or using a liquid soap gel. When the apocalypse has set upon us, though, and all you've got are three bars of Ivory to keep you smelling fresh for an entire year, we doubt you'll want anything more.
Since these are concept designs, these clever soap graters aren't available anywhere. Of course, you can always just use a regular cheese grater, collect the flakes and put the bar of soap away for another day.