Qingpu district police have arrested four people who made 300,000 yuan ($49,005) selling expired motor oil that they repackaged under well-known brand names, police said Monday.

The suspects were charged with producing and selling fake and substandard products, according to a press release from the Qingpu District Public Security Bureau.

Police busted the group's production workshop in Baihe town in Qingpu district on June 5 after residents complained about the oil being stored there.

Officers seized more than 17,000 liters of the lubricant and 5,000 labels for motor oil brands such as Mobil, Shell, Castrol and Great Wall, police said.

One of the four suspects, surnamed Zhang, had worked as a sales representative for a motor oil company. He quit his job in 2012 and began working with two friends, surnamed Lin and Zhou, who were certified to dispose of expired motor oil.

Rather than properly dispose of the expired oil, Lin and Zhou sold it to Zhang, who remixed it and repackaged it under the brand names with new expiration dates, police said. Zhang and the others sold the motor oil to stores at a discount.