Sometimes by being familiar with the site itself, you can guess what the cans might have contained.
For example, these cans at left were found at the Lahontan site.
Not a garden, or even an attempt at one, did we see in this place; everybody here lives on canned goods." Most of the cans you'll run across are too rusty to readily identify what was in them, unless they have an unusual shape.
The first can opener consisting of the now familiar sharp rotating cutting wheel was invented in 1870 but was considered too difficult to operate for the ordinary consumer.
From this time, lightweight tin cans could be used.
Felinfoel Brewery was a major supplier to British armed forces abroad in the Second World War - cans saved a great deal of space and weight for wartime exports compared to glass bottles, and did not have to be returned for refilling.
The key development for storing beverages in cans was the interior liner, typically plastic or sometimes a waxy substance, that helped to keep the product's flavor from being ruined by a chemical reaction with the metal.
Another major factor for the timing was the repeal of Prohibition in the United States at the end of 1933.