After hours of painstaking work by an expert locksmith, the contents of a historic vault hidden for decades in the 120-year-old Dineen building on Yonge Street will finally be revealed by CBC Toronto Wednesday evening — sparking excited speculation about what could possibly be in there.

The safe, which itself is a historic gem built before the turn of the last century by Toronto's J & J Taylor Safe Company, was a challenge to crack Tuesday evening. It had a broken spindle — the dial used to enter the combination — when it was uncovered during renovations in 2011.

Toronto safecracker Josh Pothiers has analyzed the 19th century vault and knows how to open it. (Amanda Margison/ CBC News)

"It looks like the spindle was broken off and that's usually done in frustration," said Josh Pothiers, who's with a company called Toronto Safecracker.

Armed with a drill, a paper clip, a remote camera and a lot of patience, Pothiers got down to work Tuesday evening.

"It's a lot of pressure," Pothiers said. "I'll get it open but if I say how long it will take I might jinx it. So I'm not going to speculate on that."

He was eventually able to open the vault, but it took him two-and-a-half hours from start to finish.

"We had to call a lot of different locksmiths to find someone capable," said Kane Willmott, whose company, iQ Office, leases workspace in the Dineen building, which is at 140 Yonge Street just south of Richmond Street.

Kane Willmott's curiosity made opening the vault a reality. (Petar Valkov/ CBC News)

Willmott's curiosity was piqued the day he saw the locked vault. Refusing to believe it couldn't be opened, he persevered until he found Pothiers, who said there has never been a safe he couldn't crack.

"I can't wait to see what's in there!" Willmott exclaimed.

So, what does he think is inside?

"I'm hoping for diamonds and gold but it could be fur."

Fur is a good guess considering the yellow brick building was the showroom, workshop and office of the upscale fur and hat making company, W. & D. Dineen, until the 1930s.

The Dineen building in 1900 looking north from Temperance Street. (City of Toronto Archive)

The building then saw a series of owners and many tenants, some whose names are carved on a stone registry in the entrance, another discovery made during renovations carried out by the current owner, the Commercial Realty Group.

There was a barrister, an insurance broker and a company called the Never Slip Line Holder, all remnants of a different era and all clues to what may be inside the vault.

"Maybe it was an eviction and the disgruntled tenant didn't want the landlord to have access to the goods inside the vault so they broke the spindle," said Kaitlin Wainwright, the director of programing with Heritage Toronto.

Heritage Toronto's Kaitlin Wainright hopes the vault contains documents that tell the story of a Dineen tenant. (Amanda Margison/ CBC News)

The Dineen building has several steel vaults, a common feature to protect against fire and flood in 19th century buildings, but this one was the only one unopened.

Wainwright said there are so many possibilities, but she told CBC Toronto she's hoping for documents with dates and names.

"It's likely that whatever we find in here, if we find anything, it will be the story of one person or a couple of people and that's really valuable. It's what shapes the fabric of this city."

Log on to cbc.ca/toronto or tune in to CBC TV at 6:00 p.m. to see what's in the vault.