Bro, it was really cool (although useless) to throw that idol into the shop. But I know an even more obscure trick: you can sell an idol or crystal skull, by placing it on the top of a vault. Check out my latest screenshots on Steam.

In your Drainmec video, you couldn't find the key and I was surprised you didn't notice where it was. It was under a push block, and you bombed that area, causing the key to get crushed.