After that woman leaves, Zhang says she feels really sorry for such behavior. Many Chinese look down on toilet cleaning as a job and tend to mistreat cleaners.

"When we have difficulties, I'm here to comfort my wife," Zhao says.

4 pm: When Zhang is cleaning a squatting unit, she hears someone say: "Thank you" in Chinese.

The speaker is 20-year-old American tourist Chelsea Hawkins. She tells Zhang she is very grateful for her because she keeps the toilet clean and tidy. Zhang is surprised and smiles.

Zhang says that her work is acceptable and she is "very proud of it".

"I could do more for visitors, for Beijing," Zhang says.

5 pm: She has already worked for 12 hours now, and she's tired but happy, she says. After a simple dinner of scrambled eggs with tomatoes, she takes a walk around the area. Since she has been put in charge of the toilet, she has never strayed more than 1,000 meters from it.

"I may be needed in the toilet anytime. Hopefully, I will have an opportunity to visit the temple sometime," Zhang says softly.

10 pm: After the last toilet-user has left, Zhang boils some water and takes a shower in the toilet. She will repeat the same cleaning routine day after day. Because she will have an important guest in her house the next day, she decides to spend 10 yuan in a public bathhouse in a nearby hutong (alley) that evening.

"My daughter-in-law is coming to Beijing," Zhang says in delight.

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