Thirty seconds.

That’s how much time Stephen Mills said it took him to open a safe that was sealed for at least 40 years — a feat even locksmiths had declared was probably impossible.

“I’m pretty sure my jaw dropped to the floor,” Mills, a resident of Fort McMurray in Alberta, told The Washington Post on Wednesday. “I was like, ‘Oh, my goodness.’ ”

Since the early 1990s, the unwieldy 2,000-pound black metal box has been tucked away in the basement of a museum in the small town of Vermilion, located around 300 miles northeast of Calgary. In prominent all-caps yellow lettering, the safe bears the name of its former owner, the Brunswick Hotel, a local establishment that closed in the 1970s, the Canadian Broadcasting Corp. reported.

But when the safe was donated to the town museum, a vital piece of information was missing: the combination.

For years, the museum’s staff repeatedly tried to get it open, turning to former owners, the safe’s manufacturer and a locksmith for help, longtime volunteer Tom Kibblewhite told CBC Radio’s “Edmonton AM” this week.

The hotel’s manager couldn’t remember the numbers, according to CBC. A call to the manufacturer proved fruitless, the Vermilion Standard reported. The locksmith provided possible combinations, but none of them worked, Kibblewhite said.

“We had a conference call going with several of us standing around the safe, trying what the locksmith was telling us,” he said.

After the safe’s door still refused to budge, Kibblewhite recalled the locksmith saying that the safe may have been left undisturbed for so long that even with the right combination, “the gears weren’t falling into place fast enough.”

In other words, the safe was too old and would probably never open again.

So the impenetrable box remained in its basement exhibit, its contents a mystery until last month when Mills and his family stopped by for a tour while on vacation during a long weekend.

“Something that we’ve learned is everywhere we travel, we certainly enjoy small towns because they all have something to offer,” the 36-year-old told The Post.

The museum, which used to be the town’s school, caught Mills’s attention, so he decided to bring his wife, their two children and members of his extended family to take a look around. There, the group met Kibblewhite, who guided them through the exhibits, eventually leading them to the safe.

As Kibblewhite detailed the safe’s history and the efforts to get it open, Mills said everyone was amazed.

“I said to him, ‘That’s quite the time capsule that you have there, and nobody knows what’s in it,’ ” Mills recalled.

Aware of the fact that numerous attempts had been made before him by professionals and other visitors, Mills, who works as a machinist and welder, said he had no expectations when he knelt down and put his ear against the door.

“I was like, I gotta get down and try this for a laugh,” he said. “I was doing it as a joke for the kids, trying to be like in the movies, more or less.”

Mills noticed that the numbers on the safe’s dial went from zero to 60, so he went with 20-40-60.

“I took the numbers out of thin air, like right out of my head,” he said. “20 three times to the right, 40 two times to the left and 60 one time to the right, and tried the door and it cracked open.”

Disbelief abounded.

“Right away, I stood up, and I was like, ‘I’m buying a lottery ticket tonight,’ ” Mills said.

Kibblewhite told CBC he “couldn’t believe that it was happening.”

For four decades, the town’s residents and visitors had wondered about what lay hidden inside the safe. Gold? Jewels? Other fantastical riches?

“We were hoping there were gold bars or sacks of gold or something,” Kibblewhite told the Canadian radio station.

Instead, as the heavy metal door swung open and the group eagerly peered inside, all they saw were a few scraps of paper and “a pile of dust,” Mills said.

The papers, which were all dated from 1977 or 1978, included part of a waitress’s pad that had an order for a mushroom burger and a pay slip for a hotel employee who received a “total payout of $9 and some cents,” Kibblewhite said.

The lack of treasure, however, did little to damp the mood. Photos taken moments after Mills cracked the combination showed Kibblewhite grinning broadly as he examined the pieces of yellowed paper.

“There was no way to be disappointed when you had so much excitement at the fact that it actually opened,” Mills said. “It was just total disbelief that it actually worked."

Though Mills may have finally given the museum the answer it long searched for, Kibblewhite told CBC the plan for now is to err on the side of caution and keep the safe open.

“We’re going to disable it enough so it cannot be locked again,” he said.

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