We may think of tin cans as something to be tossed in the trash, but archaeologists are now making a specialized sub-science of them.

With their distinct labels and shapes, tin cans can be used to date a dig site and learn more about the people who ate, worked and lived there.

The inventor of tin-can archaeology, the late Jim Rock of Yreka, California, recently bequeathed to Southern Oregon University his huge collection of the often rusty, broken and bullet-riddled containers, along with his detailed books and papers, meticulously documented to identify a can midden in time and space.

“Jim Rock was with the Forest Service and collected these all his life. He was really the champion of cans in the early days of the science,” says Chelsea Rose, staff archaeologist and adjunct faculty member at Southern Oregon University. “He did the foundational chronology and detailed how cans evolved over time.”

Rock was known as the “can guy,” and people from all over would bring him their old-looking cans, says Rose, joking that, as their new curator, she is getting known as “the can lady.”

While few of our ancestors ever signed and dated an artifact made of stone, bone or wood, they did leave cans, which have writing on them and are practically imperishable, she notes. In addition, our forebears were not too particular about recycling and left them all over the place, able to be given a sort of provenance.

Rock’s research has been archived at hanlib.sou.edu/cans. His collection is curated at the SOU Laboratory of Anthropology. The collection and research, Rose notes, have become a main reference point for cans for the whole world.

Tin cans were invented about 1810 in France and England after Napoleon Bonaparte in 1809 issued a challenge to invent a method for preserving the food needed to feed an army. Tin cans were soon commonly used in those nations’ navies, so grateful sailors thousands of miles from home could eat peaches and beans. They reached the general population in the late 19th century. After World War II, Rose says, vast marketing campaigns made cans smart, modern and in demand, relegating fresh produce to the back burner. Now it’s the reverse, she says, with fresh food preferred.

Rose does presentations about cans and, showing them at SOU’s recent Literary Arts Festival, she noted the progression of the Log Cabin syrup cans which, unforgettably, came in the shape of a log cabin.

They were considered junk until the 1970s, when a number of archaeologists realized their science could focus more on recent Euro-American artifacts — and they found that cans told them not only about settlements and mining, railway or logging camps, but cans moved all over the world, so they outline trade routes.

“Sometimes it’s the only way we have of telling their story,” she says. Cans also are ethnic markers, as Italians, Chinese, even the Sikhs of India (who were in early Oregon) had their distinctive food preferences.

In the annual trash cleanup of Yosemite National Park, she says, archaeologists are surprising volunteers by teaching them that most of it is litter, but here and there are bits of our history that must be saved and studied.

“You may be hiking in the woods and imagine no one’s ever been here, but suddenly, there’s a can or maybe a pile of them,” she says. “If you can get them to tell their story, you can learn a lot about the past.”

— John Darling is a freelance writer living in Ashland. Email him at jdarling@jeffnet.org.