@Tfmonkey
Regarding the Chinese "gutter oil" meme that you mentioned on the show yesterday, I learned that people don't actually harvest oil from sewers and gutters for cooking since the 2010's for cooking unless they want to commit a significant crime on a matter that the CCP is apparently anal about. What you're seeing is business owners performing legally required maintenance.

Have a watch:
https://www.youtube.com/watch?v=G43wJ7YyWzM