If you happen to find some remnants of woven wool in your attic - in red, white or blue and marked Fort McHenry - the Smithsonian Institution would like to know.
Two hundred years after a massive flag was hoisted over the fort in Baltimore that withstood a British attack, Americans from Maine to California may still have fragments from the original "Star-Spangled Banner.''
Not long after the huge 30-foot by 42-foot flag inspired an 1814 poem by Francis Scott Key that would become the national anthem, its caretakers began snipping off pieces.
By the 1880s, about 20 percent had been lost.
Cutting up a flag today could be considered desecration, but back then, the clippings were given away as keepsakes.
"It was such a monumental moment in time that people felt they wanted to hold a piece of that history,'' said Jennifer Jones, a curator who oversees the flag at the Smithsonian's National Museum of American History.
The Star-Spangled Banner is showing its age now, but the Smithsonian carefully preserved it for display. Housed in a chamber that keeps oxygen and lighting very low and temperature and humidity constant, it should last for generations more.
And lest we be too harsh on our forebears, Jones credits the revolutionary-era tradition of souvenir-keeping for maintaining the flag's value, which "probably led to its ability to survive 200 years.''
With Maryland celebrating its Defenders' Day on Friday and America's victory over the British 200 years ago Sunday, at least two families recently inquired whether their fragments might have historical value.
Museum conservators are using microscopes, x-rays and other equipment to analyze their weaves, stains and soils to see if they match. Family histories and documents also help prove provenance.
Since the flag came to the Smithsonian in 1907, about 17 pieces have been donated or bought at auction. The museum last acquired pieces in 2003 but has no plans to try to recover them all or reattach them to the original flag.
It's difficult to determine exactly where each piece came from, and the Smithsonian wants to lend pieces to other museums.
But some are more valuable than others. The 15th cotton star was cut away sometime before 1873, and remains missing.
"We'd love to have that back,'' said the flag's chief conservator Suzanne Thomassen-Krauss. "That one I might put back on.''
Key's poem propagated a misunderstanding that persists today, by suggesting that the garrison flag had withstood British cannon fire. In fact, soldiers hoisted the huge American flag at dawn as the British fleet retreated, replacing a smaller storm flag that had flown during the bombardment. The garrison flag flew at the fort for another year or so, until it was acquired by Fort McHenry's commander, Lt. Col. George Armistead.
The first documented clipping was taken in 1818 at the request of a widow, to be buried with her husband who fought at the battle.
The Star-Spangled Banner was passed down through Armistead's family and protected through the Civil War. In 1873, his daughter Georgiana Armistead Appleton lent it to historian George Preble for a lecture series across New England.
Historians believe Preble made many clippings for friends, patriotic citizens and his own family.
Some pieces turned up in Minnesota, where another Armistead daughter settled. Another piece was placed in a keystone for the Francis Scott Key Memorial in San Francisco's Golden Gate Park. Historical societies have donated fragments to the Smithsonian, and the U.S. Naval Academy sent a thumb-size piece in a gold frame.
"We suspect there are more fragments that have just lost their history,'' Thomassen-Krauss said. "People see them, but they don't know what they are.''