It s really unlucky, every time I am lazy to smoke in the toilet, I come across the old version and

Safflower oil, Yunnan Baiyao spray.

The main reason for the sinking of the toilet door and the fact that it touches the floor every time it is closed is that the toilet door is deformed in the sinking. If it is a door with mortise and tenon joints, the solution is to remove the door, correct it at the same time, and smash the wooden plug at the mortise and tenon joint to fix it.

Maybe they feel embarrassed to run into a student when they go to the toilet, so they go to the toilet while the student is in class.

It's normal to have rats on the fourth floor, usually climbing up through the sewer pipe, check the floor drain, especially the hidden ones that are not used, and replace them with good metal floor drains.

It can remove the odor, and in the eyes of several people, the smell of smoke is good after all. After a long time, it has become a habit. That's it.