and you break out the slow cooker to make a delectable stew. But once you start the cook and put the lid on top, you notice a little hole in the otherwise all-glass lid. "That's odd," you think.

Who doesn't like push-button cooking? If you've bought a brand-new slow cooker, it may come with a glass lid that can be secured to the top of the cooker via latches on the side. It may look like ...