They do the dirtiest and most tiring work, but they are necessary to ensure that our lives are clean.
They deal with sludge and smelly water all day long, but they give our city a beautiful and clean garden.
They are just that - professional cleaners.
Keep the dirt to yourself, give the clean to the world.
Diligence brings not only a "cleanness" to the world, but also a "cleanliness" to the beauty of the soul. ——Clean and "purify" the world.
Ordinary people, but great heroes.
Mission: There is no high or low profession, and no profession is easy.