The ingredients of cans are mainly aluminum alloy (lighter, such as cans for canned beer and cola) and tinplate (heavier, such as cans for Wangzai milk), and then the surface of cans in contact with food will be coated with an inert material, which can prevent the chemical reaction between the contents and the cans, or the metal elements in the cans from dissolving out and migrating into the food, but this is generally limited to normal temperature or high temperature.

Like the popcorn operation in the short video, the temperature should exceed 150-200 degrees. At such a high temperature, whether the internal coating will be destroyed is uncertain, but it should be risky. This practice is very unsafe, especially easy to burn, but this is second. The most important thing is that the surface of the cans is painted, and the painted surface may be decomposed into various toxic and harmful gases after heating. Moreover, the heating was not considered at the beginning of the design of cans, and the melting point of aluminum is also low, which also has the risk of melting.

Now it is very simple to make popcorn at home by yourself. You can make it directly in a pan. Why do you need to find a can? It is extremely dangerous and may be toxic, and it takes a lot of time. You can only pop it one by one, which is just to make it fresh. Like in the news, it's not worth the loss to be in danger because of a moment's curiosity, so I personally think that some operations are just to look at them, and don't imitate them at will, because there may be some potential dangers that we haven't discovered, so don't always wait until there is an accident to know regret and fear.