Back in the dark ages when I was in (US) grade school, they served us milk all the time in sealed plastic baggies. (Much smaller than the ones in the video) Each baggie came with a sharpened plastic straw, which you jabbed in and drank through.
A personal small-scale example: an acquaintance of mine bought a bobble-head figure at a yard sale for like a dollar, and I helped her sell it on eBay; we got $300 or $400 dollars for it..
And where was she hiding the can if it wasn't in her purse?
It's probably sad I know that, but oh well.
The Wikipedia article on the Pillar has an explanation, but personally my eyes glazed over after two sentences.