People who watch "Antiques Roadshow" on TV may be inspired to clean closets and hunt through attics for family heirlooms that, just maybe, could be worth thousands of dollars.

But before running off to the closest antiques dealer with an armful of Amish quilts and century-old Teddy bears, be warned: your treasures may not be as valuable as you think they are.

One of the drawbacks of "Antiques Roadshow" is, after watching it, people may think they've learned enough to appraise their own valuables. But, more often than not, antiques experts don't recommend self-appraising, unless it's to get an idea of what the object is. Finding out how much the object is worth should be left to the experts, they say.

Stuart Slavid, a "Roadshow" appraiser who works for Skinner Inc., an auction house in Boston, said self-appraising takes a lot of time and effort and often ends up being a waste of both.

"You almost need to know a little bit about what you have to get started, and then you can Google it," he said in a telephone interview from Boston. "But a lot of times you don't even know what it is, and if you don't know that, you don't know where to start with reference books and price guides."

Marsha Bemko, an executive producer of "Antiques Roadshow," said one of the biggest problems is most people can't distinguish an original from a reproduction.

"If I could write a book about how to recognize a fake, I'd be rich," she said. "There are no short cuts to being an expert. You have to look at a lot of things to recognize the true object among the fakes."

Many appraisal Web sites work from photographs of the object being appraised. Bemko said the idea of appraising something's value from a picture made her skeptical of how accurate the appraisal would be.

"It's like buying a house," she said. "Yeah, you look at pictures of the house, but that's not the same as walking through it."

With antique furniture, for example, a hairline crack in one of the legs would lower the value by as much as half. And that imperfection wouldn't be visible in a photograph, so the appraiser wouldn't see it. When the owner tried to sell or insure the furniture for the appraised price, he or she would find out the appraisal was misleading.

When it comes to collectibles, such as Matchbox cars, the value can span the spectrum depending on the car's condition, said David Carroll, collections manager at the Utah Museum of Fine Arts.