The weird thing about the Chinese sewer grease to me is that there is enough waste grease/oil to actually be "mostly" grease in the sewers in the first place (at least insomuch as it can still be used to "deep fry" anything, and doesn't just evaporate whatever liquid content and then burn instead). I mean, how the fuck did that even get started? Also how do they even reliably cook with this shit? "Sewer oil" seems like it would be insanely unreliable to cook with, since the smoke point, total oil content etc would probably vary all the time, right? Or is this sewer oil actually stable at some percentage of oil as a relative constant. It's fucking bizarre.