Critomancy is an ancient form of divination of cakes. The paste of cakes which were offered in sacrifice were divinated. Omens were drawn from the flour spread upon them after being strewn upon sacrifices.

I would guess that these were edible cakes, but I'm not sure.

I, for one, have never seen a ceremonial offering of soap to the gods... Oh Great and Powerful Stink God! Bathe thyself and be clean!