Together with the adenoids at the back of the nose, they form a ring of lymphoid tissue that is thought to filter out bacteria and other germs that enter our bodies through the mouth or nose. Several bacterial diseases, most commonly strep throat, but also the much rarer diphtheria, tend to infect the tonsils, and can be easily seen as a white or gray membrane sitting on the inflamed and swollen tonsils. The tonsils have many holes, called crypts, on their surfaces. This helps in them fighting infection by offering a much larger surface area than a smooth perfectly flat surface would. These crypts can be easily seen in normal tonsils as slits or folds in the surface of the glands.
Some people have a tendency to develop clumps of debris in the crypts of their tonsils.
The debris can be composed of dead cells, food particles, bacteria, and mucus and is normal. As happens with any organ exposed to the outside, the surface of the tonsils is constantly sloughing off dead cells, helped by the friction of food passing over them. In some people, these cells and the other components of the debris collect in the crypts, forming the balls you describe. While infection may cause more debris to collect, and therefore lead to larger or more numerous collections of debris, the balls themselves do not represent infection and need not be treated with antibiotics unless there is other evidence that the tonsils are infected. This is one doctor who makes housecalls.