“The most pleasant way of cleaning the teeth and removing even the tartar, is sour milk. Rub the teeth with it, and then rinse the mouth with warm water, and you will feel how clean the teeth have become.”

Several things can cause it, but usually it’s caused by dehydration.

Sometimes drinking more liquid helps.

Sometime it doesn’t help because the tissues won’t rehydrate. (Stress is one thing that can cause this.)

Drinking water followed by a pinch of salt helps break up mucus, as long as it doesn’t contain pus.

Putting a dab of cayenne pepper on the tongue and rinsing the mouth with club soda can help break up the “molasses” or “pancake batter” consistency of mucus.