Consider the following. Cats rarely reject a proffered piece of food on the basis of it's taste. They use smell as the discriminator to decide if something is likely to be good tucker or not. Using their sense of smell, the cats subconsciously realise that earwax has a nutritional value - specific olfactory receptors will be triggered by the scent of the fatty acids, the cholesterol, and also the dead skin cells (mostly protein). Cats are specifically attuned to the scent of animal proteins, hence their preference for meat - also the reason why cats hungrily devour earwax (and also love freshly picked scabs). The ratio of smell receptors to taste receptors is virtually reversed in cats and humans - as such if something smells good but tastes like sh*t then we won't eat it, but if a cat likes the smell of it, it has to taste f*cking awful before it won't eat it. A cat will eat small lumps of plasticine if they're covered in gravy. Try it - it's non-toxic and you can pepper your cat turds with interesting multicoloured lumps.