Cashews don't come cheap — one pound at retail can cost you $15. Here's why they're so expensive.

One kilogram of cashews can cost $10 wholesale — over seven times as much as peanuts. And in the US, retail prices for raw whole cashews can reach $15 per pound. But cashews are more complex than most other nuts. Each cashew kernel grows inside a toxic shell. It must be carefully extracted from this shell and rigorously processed to ensure that the caustic liquid inside the shell is completely destroyed. So, how are cashews processed? And is this what makes them so expensive?