SHANGHAI, July 2 (Xinhua) -- Many Shanghai residents may be experiencing headaches as they face daily tests as to which piece of garbage goes in dry refuse and which goes in recyclable.

A man surnamed Liu, however, may not be that grumpy after all because he managed to retrieve 18 pieces of gold ornaments from his trash.

The Shanghai police told Xinhua that a resident surnamed Liu, who lives in the Putuo District of the city, threw a cardboard carton away a few days ago. He sorted it correctly by putting it into a waste bin labeled recyclable, but he received a call about his trash from the local residents' committee.

Xun Siwei, a garbage collector in the neighborhood, found that the carton contained a plastic bag full of golden accessories.

"I looked at the gold, and my heartbeat went up. They are gold, but I know they belong to someone else. I can not keep them," said Xun.

Xun reported his finding to the police on June 28. Police checked the accessories and found a name and birth date inscribed onto a golden badge. Based on the details, police contacted the residential neighborhood Liu lives in and got in touch with him.

Liu said had been searching for the gold for three years, but failed to locate it.

"Getting these valuables back is the boon of garbage sorting," he said. "My family will spare no effort in carrying out the garbage sorting campaign."

Shanghai is widely promoting a mandatory garbage sorting system, which requires residents to throw away garbage at a fixed time and place. A disposal site is designated for every 300 to 500 households, where volunteers carefully check whether the household waste is accurately classified.

The city enacted a set of regulations on household garbage sorting and recycling starting Monday, which requires residents to sort household garbage into four categories: dry refuse, wet trash, recyclable waste and hazardous waste. Individuals who fail to sort garbage may be fined up to 200 yuan (about 29 U.S. dollars).

Mr Liu's gold being retrieved has gathered interested commentators online. "There is really hidden gold in your garbage," one netizen exclaimed.

"Have faith in garbage sorting, it will bring you good luck," anther netizen commented.