Most of us have felt a small lump at the back of our throats, an annoying little bulge helplessly trapped in the pockets of your tonsils until you manage to squeeze or pry it free and spit it out. What the heck are those things?

The good news is SciShow says they’re not dangerous, even if the yellowy things make your breath smell a little.

“Your tonsils are part of your lymphatic system; they work with a bunch of other tissues to get rid of waste and fight off infections,” host Michael Aranda explains. The crevices at the back of your throat “can collect dead cells, extra mucus and food debris or other particles that somehow end up in your mouth.”

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When that debris turns into a tonsil stone, it has calcified in its cosy little pocket as a side effect of what your body’s white blood cells have done to protect you against foreign objects.

“When the white blood cells are finished, hard particles remain on the tonsils,” Live Science says. “Most people simply swallow what is left behind and never know that it was there in the first place. If the particles are lodged into the crypts, though, the particles will continue to grow” into tonsil stones.

If this is happening all the time and causing serious irritation, warranting visits to ear, nose and throat doctors to have the stones taken out, removing the tonsils with surgery is an option.

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