(CNN) -- It's amazing what a little spring cleaning can turn up.
Fourth-grade teacher Michelle Eugenio was in for quite a shock when she stumbled upon a document dating back to 1792 while emptying out an old classroom at the school where she teaches in Peabody, Massachusetts. She found the document, apparently a receipt for payment of a debt, buried among some old textbooks and papers.
"I looked at it, and I saw it was in plastic, which kind of told me there was a chance it was real," said Eugenio in an interview with CNN Radio. Eugenio says she shared the document with her social studies classes, and her students urged her to find out if it was real. She brought it to the Peabody Historical Society, which was able to authenticate the 218-year-old find.
It turns out the document originally belonged to Jonathan Bates, a Vermont man who had served in the Continental Army during the Revolutionary War. The paper appears to convey that Bates had paid off a debt, according to Paul Carnahan, a librarian with the Vermont Historical Society in Barre, Vermont.
"What's fascinating is that this turned up in a school classroom so far from Vermont," said Carnahan. How that happened is uncertain. Eugenio says the school building where she found it only dates back to the 1930s. However, she does have a theory.
"The only thing I can think of is that a teacher who was there before me or a student brought it in to show. Then it was put up onto a shelf and forgotten about," said Eugenio.
The document reveals little else about Bates beyond his military service and his debt payment, according to Carnahan. He says records show Bates was born in Williamstown, Vermont, and died in 1808 at the age of 63.
Bates' gravestone was recorded during a WPA inventory in the 1930s and in burial records in Williamstown. But Carnahan says people who have gone to the cemetery looking for the grave in the past week were not able to find it -- possibly because a lot of the gravestones in the cemetery are damaged or have deteriorated over a period of time.
You might think a document like this would be worth a pretty penny. But Eugenio says she doesn't plan to test the market.
"If I hold on to it I'll show it to my grade next year. Or, we'll give it to the historical society. The kids are excited. To find something of that kind of historical value is really important," she said.