The normal amount of mucus and fluids produced by a nose in room temperature is 32 ounces per day! Your body produces all those fluids to help filter and warm up the air that you take in.
While some of those fluids leave your body by, say sneezing, most if it doesn't. Guess where most of it goes? It falls to the back of your throat and you swallow it. This means that, in a way, we are all designed to eat our boogers!