WORCESTER - We’ve all lost the keys to our cars, some of us on a daily basis. But it takes somebody truly special to lose the key to the city of Worcester, and the city and police in North Adams are asking who that person may be.

“Help find the rightful owner of this pristine Key to the City of Worcester, Massachusetts,” Worcester posted on its Facebook page Wednesday. As of Friday afternoon, nobody had come forward to make a claim, a city spokesman said.

The key is approximately 6 inches long, with a heart-shaped handle and teeth in the shape of a ‘W.’ Emblazoned with the name “Worcester,” the key is gold-colored and came in a satin-lined box stamped with the name of Mayor Andrew B. Holmstrom, who served from 1950 to 1953.

North Adams police reported finding the key on Monday and posted a picture of the missing keepsake on Facebook on Tuesday, looking for help finding its owner.

Unfortunately, there aren’t a lot of clues.

“It turned up,” William D. Wallace, executive director of the Worcester Historical Museum, said simply when asked what is known about the key. “There seems to be no log of who received the keys.”

But through the archives of the Telegram & Gazette and the Worcester Historical Museum we can learn a little about the history of the key-giving tradition in Worcester.

The practice of cities giving keys supposedly originated centuries ago when town gates were locked at curfew and keys were given out only to a trusted few.

In Worcester, the ceremonial key-giving tradition began in 1924 with Mayor Michael J. O’Hara. The key was designed by John W. Odlin of Tory Fort Lane, and on one side of the shank read “A Town 1722, A City 1846,” and on the reverse side was the word “Worcester.” Like the key that has been found, there was a heart-shaped handle and W-shaped teeth.

The mayor decides who the key recipients will be, and they have ranged from the famous to, well, the cud-chewing.

Over the years the key was awarded to everybody from evangelist Billy Graham toactress Veronica Lake and newsman David Brinkley and Henry Hite, who reigned as the world’s tallest man at 8 feet, 2 inches, and Elsie the Cow, the mascot for Borden Dairy Co.

Some were impressed with the honor.

Movie butler Arthur Treacher wrote a thank-you letter to the city after receiving his key when he opened a fish-and-chips store in Webster Square. Bandleader Doc Severinsen mentioned his key on national television.

Others, like Irish Prime Minister Eamon De Valera, never even made it to the city - as the key was presented to him during a stopover at Boston’s Logan Airport.

By the time of an April 1986 Telegram article, it appeared no one had ever refused a key. But on at least one occasion the mayor has refused to give one, according to the article. In 1981, Mayor Jordan Levy declined to give a key to civil rights activist and future presidential candidate Jesse Jackson, who Mr. Levy felt had lent moral support to terrorists by making a controversial visit to officials of the Palestine Liberation Organization.

Mr. Levy couldn’t win with the key-bestowing. In 1980, he got in trouble with the American Civil Liberties Union for presenting a key to the city to members of a South African horseshoe team.

“The ACLU argued that it was wrong for the city to be giving out keys to visitors from a country condemned for its treatment of blacks,” Telegram reporter Chris Pope wrote. “In Levy’s defense, he said he didn’t know the visitors were from South Africa until they walked into the City Council chamber to collect the honor.”

Other mayors also received criticism for their key giving, according to Mr. Pope.

Mayor Israel Katz once took to the council chamber floor to blast predecessors for giving out keys to “every Tom, Dick and Harry.” He also, citing precedent from other cities, awarded the key to Elsie.

Mr. Katz was also notable for changing the key design in 1974.

The original keys - 500 were ordered at $1.50 apiece in 1924, according to Mr. Wallace - were either gold-painted metal or solid brass or bronze (the Telegram and the Worcester Historical Museum have different accounts of the materials).

Mr. Katz had the keys shrunk and mounted on a 4-inch-by-6-inch walnut plaque. The mayor’s name is engraved on a gold-colored aluminum plate and the recipient’s name is engraved on another; the plates are mounted above and below the key. The handle of the key was also changed to a Shamrock pattern.

“It was thought to be a cost-saving measure,” Mr. Wallace said.

In 2012, current Mayor Joseph M. Petty restored the original design. The keys are made of solid brass and are manufactured by students in the machine technology program at Worcester Technical High School.

The key comes in a leather box stamped with “City of Worcester, Honorable Joseph M. Petty, Mayor, Manufactured by the students of Worcester Technical High School, Machine Technology Program.” The only thing different about this key and the key found in North Adams is the wording. Instead of “A Town 1722, A City 1846,” new keys are stamped with the mayor’s name on one side and “Worcester, Massachusetts” on the other.

“People love getting the key. They really appreciate it,” Mr. Petty said, listing recipients as city retirees, Eagle Scouts, longtime residents and married couples, visiting dignitaries and more. He said he has given out roughly 125 keys in the past two years.

But the most important feature of the new keys?

Mr. Petty said there’s a list of recipients in the mayor’s office.