04/09/2014 10:40 am ET Updated Jun 09, 2014

You Won't Believe What This $15 Thrift Store Purchase Is Worth

You might call it shopping. My husband thinks it's hoarding. I call it gambling. And I'm addicted.

I'm addicted to the possibility of uncovering treasure. The chance that a small "investment" (my husband demanded I use quotes there) could transform into glorious riches.

I know the system is rigged. I know the odds are stacked or everyone would be doing it. I know it's almost always a waste of money. But there is the almost. Which means there's the chance.

And stories like this one, about an old, dusty violin bow -- rare tales that fuel delusions, like my addiction to buying old junk at thrift stores.

Like Colorado before the Gold Rush days, the city of Boulder is a yet unmined mountain of booty.

Boulder's Craigslist is the glorious result of super rich people living in historical homes that they want to renovate, while recycling everything, but without needing to make any actual money off anything. Environmentally friendly millionaires help stock the shelves of local thrift stores.

We will probably never know the backstory of the man with the violin case. But Shirley Nelson will never forget the serendipitous encounter with him in the parking lot of the Ares Thrift Shop on Spruce Street.

The Boulder woman admits she truly feels for the guy. He didn't know.

In the moment, she didn't either.

Nelson was on her way into the thrift store, when she saw a man getting out of his car carrying an old, weathered violin case. He was on his way in to donate it.

Nelson, who has been tinkering with learning to play the violin for about eight years and whose daughter plays in a youth orchestra, intercepted his path.

"It was all beaten up. It smelled and looked like hardly anything," she says. "But I felt something with the case -- this really positive energy."

Inside, she found a chipped violin with broken strings and a dusty, used violin bow. On a whim, she asked if he'd sell the case and its contents to her on the spot for all the cash in her wallet: $15. The man, who was presumably about to get nothing for the donation anyway, took the money and handed her the case.

She brought the case and its contents to Eric Paulu, one of the rare, professional bow-makers and experts in the state and one of only a few dozen across the country. She'd only met him once before, when he repaired her daughter's bow. She wondered if her find was worth anything.

"I had to warn her, because there are a lot of imitations made -- imitation fine bows, fakes, in the way there are fake Picassos," Paulu says. "I told her not to get her hopes up."

Then he opened the case.

"Violins and bows end up in thrift stores and pawn shops and antique stores all the time. This is not what's unusual," Paulu says. "What's unusual is it had something of real remarkable value inside the case."

He recognized the wood: Pernambuco, from Brazil, the best wood for a top-of-the-line bow.

This led him to examine the metal parts. They had tarnished black-grey, not green, indicating they were sterling silver, not nickel silver, and they were accented with a special engraved ornamentation.

Then he saw the brand: Eugene Sartory. A famous 20th-century French master bow-maker. Paulu estimated the bow was authentic, about 100 years old. And the $15 cast-away item was worth at least $10,000.

After a few small crack repairs, some wood straightening and new horsehair, Paulu values the bow around $16,000.

The violin itself was nothing special, he says, probably worth less than $1,000 -- about the same price of a reasonably good, new violin made in China.

To Paulu, it's a cautionary tale. The saying, "One man's trash," rings loudly.

"This very bow could have ended up in a Dumpster really easily," he says. "That it came to the light of day is an interesting historical moment in the world of music. What a shame if it had gotten lost."

Before you toss a potential antique, even if it looks like junk to you, Paulu encourages people to do a little research. Ask an expert.

Or you can always call me. I'll take just about anything.

Read more Weird News from the weirdest city in the world, Boulder, Colo., here: Only In Boulder.