China Smack posted repulsive images of gutter oil that had been ‘refined’ to be reused and resold as cheap cooking oil for restaurants that were trying to cut costs. Street food vendors have been notoriously known to use this oil, posing a danger especially because the majority of street food is deep-fried.

http://www.chinasmack.com/2009/pictures/recycled-slop-swill-cooking-oil.html