SHANGHAI, July 11, 2012 (Xinhua) -- A skyscraper exterior cleaner does safety check in east China's Shanghai Municipality, July 10, 2012. Staying in mid-air for over six hours in a bosun's chair and cleaning the glass curtain wall of a skyscraper is a day's work for 23-year-old Wang Bi from southwest China's Guizhou Province and his colleagues. For them, attired in uniforms that offer limited ventilability, working in summer always require extra physical well-being and will power: back to the ground, they get soaking wet with a mixture of sweat and detergent. Strenuous as the work is, Wang Bi is contented with the payment he receives. "It's just a matter of sweats," said Wang, who has been a skyscraper exterior cleaner for three years. (Xinhua/Pei Xin)