The nasal cavity is also our nostril, which is filled with some fragile mucosal structures, and many capillaries emerge on the mucosal surface. The nasal mucosa usually secretes a certain amount of liquid for moistening the nasal cavity, protecting the mucosa and maintaining the ecological balance in the nasal cavity. After a long time, these nasal fluids will form boogers. This kind of booger is actually very normal. Although it is a little dirty, it can protect the nasal cavity very well. As long as it is not too much, there is no need to dig. If you often pick your nose to clean the nasal cavity, it may cause damage to the internal environment of the nasal cavity, and the nasal mucosa is also vulnerable. It's easy to get nosebleeds when the weather is dry.
Intestines and intestines are the body organs that specialize in digesting and absorbing nutrients and forming feces. The inner surface structure is mucous membrane, and there are specific flora in the large intestine, which is used to decompose and form feces. So the intestine is actually very dirty, but this kind of dirty is normal, otherwise how can bacteria survive in the intestine and form poop? If you often eat some food or medicine that cleans the intestines, it looks clean, but it is easy to stimulate the intestines and destroy the microbial community in the intestines.
The navel is also a dirty place. The dirtier the navel, the better the navel is closed, and the stronger the ability to resist the cold outside. Therefore, the belly button can't be completely cleaned. If you feel uncomfortable looking dirty, scrub the dirty things on the outer surface of your navel, and don't clean the deep part of your navel, because the dirty things there can protect your stomach.