Most milk cans were galvanized steel, although there was a switch to stainless shortly before the switch to tank trucks. The cans were 5 gallons, so you could carry two easily.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk