Do you know what tonsil stones are? Technically, they're called tonsilloliths, and are made up of  bacteria, dead cells, mucus, and other junk that can collect in the grooves of the tonsils. This buildup can happen due to stress, but the most common reason is tonsillitis (inflammation of the tonsils). The tonsils are supposed to trap bacteria and foreign stuff, but when they are inflamed, they are puffier. This puffiness can cause grooves in the tonsils to close up, which means any bacteria or foreign stuff would get trapped, until it's big enough to poke out of the groove. That's when you see them and get grossed out!