A money pot might carry a sweet childhood memory for some. But as early as 2,000 years ago, in today's Yunnan province of Southwest China, it meant wealth, status and power.

But it was not a piggy bank, and what was stored inside were not coins. In the ancient "Dian kingdom" (between 278-109 BC), this bronzeware container held precious seashells from the Indian Ocean, an exclusive item for aristocrats.

According to historical records and archaeological studies, most areas in Yunnan were still a barter society at that time, and shells were not popular as a currency, but were for symbolic use in the tombs of nobles.

These "shell containers" present the advanced productivity and aesthetic level of that period. Most unique is their exquisite patterns, featuring three-dimensional reliefs, depicting vivid social scenes from the ancient Dian kingdom, including sacrifices, war, tribute hunting and weaving.

People in the kingdom did not develop systematically formed words to record history, so the shell containers became the "truest and most intuitive material" for studying the civilization of the ancient Dian kingdom, says Fan Haitao, deputy curator of the Yunnan Provincial Museum.

Lu Jingjie, a cultural relics expert who has been a bronzeware restorer for more than two decades, says many bronzes are either broken or have remnants, deficiencies, rust or cracks.

There are many steps to restoring bronze, such as cleaning, de-rusting, bonding, and color-filling. The restoration work is so delicate that dental instruments are often used, says Lu.

"We pay so much attention to them to prolong the life of cultural relics so that more people can learn about this history," he says.

Preserving them properly for a long time is a more pertinent issue.

Pan Jiao, deputy director of the cultural relics protection center of the museum, says that, since 2017, to protect cultural relics, the museum has installed a wireless environmental monitoring sensor in every glass showcase.

It is used to gauge the temperature and humidity, organic volatiles and ultraviolet rays. In addition, the museum has also installed isolation platforms for vulnerable cultural relics.

To enable more people to learn about the bronze culture of the ancient Dian kingdom, the Yunnan Provincial Museum has launched online classes to popularize knowledge of the museum's collections among children.

Ye Zhisheng, deputy director of the information and imaging department of Yunnan Provincial Museum, says that, during the ongoing pandemic, it is releasing weekly online classes, teaching children to make paper products with images of the animals seen on the shell containers and other relics. So far, the video clips online have registered more than 1 million views.

"It is our responsibility to pay attention to cultivating children's interest in cultural relics and history. The concept of cultural relic protection needs to be passed down from generation to generation," says Ye.