A sore throat can be a sign of all kinds of medical maladies. You might have caught a cold from your coworkers or just cheered too loudly at that big game last night.

But if it feels like there’s an irritating lump in your throat, there might actually be something stuck back there. A whitish yellowish tonsil stone that come from the food bits, dead cells and other junk in your mouth. But even though they might be a little weird and uncomfortable and gross, they’re not really dangerous.

Your tonsils are part of your lymphatic system. They work with a bunch of other tissues to get rid of waste and fight off infection. There are actually three different groups of tonsils, but tonsil stones mostly show up in the palatine tonsils. The palatine tonsils are those two squishy patches at the back of your throat that you can see in the mirror.

If you open your mouth wide enough, the palatine tonsils are full of tonsil or crypts, which are deep folds of tissue that are designed to lure in bacteria and maximize the amount of tissue that those bacteria touch that way.

Lots of immune cells can be exposed to potential pathogens and start to build up a targeted immune response with antibodies to fight them off. But unfortunately, when you have cozy spaces for bacteria, sometimes they get a little too comfortable. These crypts can collect dead cells, extra mucus and food debris or other particles that somehow end up in your mouth, which provide a delicious breeding ground for lots of different microbes. After a film of bacteria forms, these goopy lumps can start to calcify, becoming hard structures made of calcium and other minerals. The solid lumps that form are called tonsil stones. Tonsil stones can vary in size from a couple of millimeters to a couple of centimeters. Sometimes people just swallow them or sometimes they stick around and can irritate your throat. Some bacteria that have been found on tonsil stones produce lots of sulfur compounds which might cause bad breath, but that’s usually the worst of it. It’s really rare for tonsil stones to get big enough to be dangerous and make swallowing painful or difficult.

If you want to get rid of them, you can try to pop them out using a brush or some gargling or you can go to an ear, nose and throat doctor for extra help. Tonsil removing surgery is a last resort.