I didn’t know this.
Doesn’t surprise me. You would think that whatever is in soda, beer, etc would react to raw aluminum in some way if it didn’t have a liner.
If you leave your coke or pepsi cans in the cupboard in a warm environment (e.g. Florida) you may come home in 6 months to a leaking can. Ask me how I know. We leave them in a plastic box if at all.
It must be an incredibly thin layer of plastic. I have cut up a lot of beverage cans and never noticed this film layer. It may explain why they are hard to keep paint on though.
I think it’s on the inside - there to keep the product contacting the aluminum. Although the video used caustic soda, CO2 in water is a weak acid and will react with the can.