<unk>  or sewer oil (, or ) is a general term for oil that has been recycled. It can be used to describe the practice of restaurants re-using cooking oil that has already been fried before. It can also be used to describe the processing of waste oil collected from sources such as restaurant fryers, grease traps, slaughterhouse waste, and fatbergs. Entire illicit supply chains dedicated to collecting, processing, and re-selling<unk>  have been discovered by regulators in China. Multiple low-end restaurants in China have been found to cook with illicitly-recycled<unk> . Additionally, in 2012, the Chinese government accused a Chinese pharmaceutical company of using<unk>  as a precursor for the manufacturing of cephalosporin antibiotics. In China,<unk>  has also been used as a raw material to create products like soap, rubber, bio-fuel, plastics, rooftops, and cosmetics. In the city of Shanghai, it was reported that over 2,000 buses ran on biodiesel that was made from<unk> , and many gas stations in Shanghai offered gasoline that was produced in part from<unk> . Due to China's vast industry of factories involved with<unk>  processing to produce products like soaps, fuels, plastics, rubbers, etc., there have been reports and rumors about unscrupulous people selling<unk>  for cooking and frying. However, it remains difficult to prove and prosecute such unscrupulous individuals. Food safety articles funded by PRC provincial science grants attribute continued difficulties in regulatory enforcement to the decentralized nature of the logistics chain, lack of widespread dedicated disposal/recycling options, and frequent innovations in visually and chemically disguising<unk> .<unk>  has also been used outside of China as well. For example, in England, fatbergs that were dug out of sewers in cities like London and Liverpool were later reported to be processed to produce biofuel. Reprocessing of used cooking oil is often very rudimentary; techniques include filtration, boiling, refining, and the removal of some adulterants. It is then packaged and resold as a cheaper alternative to normal cooking oil. Used kitchen oil can be purchased for between $859 and $937 per ton, while the cleaned and refined product can sell for $1,560 per ton. Thus there is great economic incentive to produce and sell<unk> . Another version of<unk>  uses discarded animal parts, animal fat and skins, internal organs, and expired or otherwise low-quality meat, which is then cooked in large vats to extract the oil. It was estimated in 2011 that about one-tenth of the oil used by restaurants in China was recycled oil. As Feng Ping of the China Meat Research Center has said: "The illegal oil shows no difference in appearance and indicators after refining and purification, because the law breakers are skillful at coping with the established standards." Some street vendors and restaurants in China are reported to have illegally used recycled oil unfit for human consumption to cook food, leading to a crackdown against such establishments by the Chinese government.
Gutter oil
Emu oil
Yu Yee oil
Lavender oil
Baby oil
Godbold's Vegetable Balsam
Phospho soda
Soybean oil