Hello,
These are tonsilloliths (literally "tonsil stones") that are a combination of bacteria, food particles, and dead white blood cells. They can cause a tickling in the throat and halitosis. Here is some more information.
http://en.wikipedia.org/wiki/Tonsillolith
http://www.doctorhoffman.com/xlith.htm
Nurse Practitioner
Board Certified Nurse Practitioner, MS, RN. Private practice and hospitalist experience.