Tonsil stones
Tonsillolith (syn: tonsil stone, calculi of the tonsil) a ball-like accumulation of food particles, bacteria, leukocytes, dead white cells, and dried mucus in the folds of tonsils. These folds are referred to as crypts. The balls of bacteria and their waste products are colored white or yellow, have a rough texture resembling cottage cheese or cauliflower, and convey an extremely foul odor. Tonsilloliths may contribute to halitosis and sore throats.
Prevention methods include gargling with salt water or a non-alcohol, non-sugar based mouth wash. A cotton swab dipped in hydrogen peroxide applied directly on the tonsil stones will not dislodge them as you may have read; it only makes one's mouth feel weird and causes gagging. The use of a water pick to clear out the crypts of accumulated debris may also help (the lower pressure tongue-cleaner attachment is recommended). A more drastic method, a tonsillectomy, is not usually indicated or recommended, but will lead to permanent relief.
It is important to remember that although tonsil stones can be uncomfortable, they are rarely ever dangerous and can be seen as more of an inconvenience than anything else.