Start your research on the Web, but be sure to have an expert look at it, too. By Kimberly Lankford, Contributing Editor May 1, 2011 Everyone dreams of finding a priceless antique in their attic. But how do you determine whether your treasure is a valuable heirloom or something better suited for donation to Goodwill? Look for unusual markings or details on the object, then search for more information online. Check auction results at eBay and specialty auction houses for actual sales (not wishful-thinking asking prices), and look up the item at a Web site that offers guidance on prices for antiques, such as Kovels' Antiques and Collectibles Price Guide 2011. If you think that your item is valuable, take it to an expert who can examine it to evaluate its condition and verify its authenticity. "You can't trust the descriptions on eBay," says Terry Kovel. "It's not that people are dishonest, but they're just not that knowledgeable" -- and fakes can easily be mistaken for the real thing. Sponsored Content You can also seek out the opinion of vendors at local flea markets and antiques shows who sell similar items, or find an established antiques shop with a good reputation. But never rely solely on an appraisal from someone who wants to buy your item -- he or she could lowball the price to get you to sell the item for a song. Advertisement Many auction houses offer free appraisals in hopes of snagging a future commission, says Rudy Franchi, of PosterAppraisal.com, a veteran appraiser on Antiques Roadshow. You can also find appraisers through the American Society of Appraisers, the Appraisers Association of America or the International Society of Appraisers. Resources for sellers. If you sell the item to a dealer, you'll typically get 50% to 70% of the retail price. You may do better at an auction house, which usually takes a 15% to 25% cut. And if you consign several valuable items to an auction house, you may be able to negotiate a lower commission, says Kovel. When deciding where to sell your items, consider how to target potential buyers and the cost of delivering items to them. Kovel is following her own advice as she downsizes her possessions following the death of her husband and coauthor, Ralph, a few years ago. Kovel says she is selling local art through a local auction house, where it may generate more interest and fetch a higher price. But for other art and antiques, she tries to attract a broader audience by listing her pieces with auction houses that have live auctions as well as a Web presence. "The auctions are listed on Artfact or LiveAuctioneers, so you can get them online from anywhere in the world," she says. For heavy items, such as furniture, Kovel relies on local dealers to reduce shipping costs. Advertisement In general, the toys that were popular with kids become valuable 30 years later, when those kids grow up and have enough disposable income to buy a piece of their childhood. For example, action figures and other boys' toys are hot right now. But if you're hoping to sell your vintage baseball card collection, you're out of luck because problems with fakes have sunk sports memorabilia prices. If you think you have a rare card that's in excellent condition, professional authentication is a must. You can get your baseball cards graded by Professional Sports Authenticators. Insuring your stuff. If you decide not to sell, you may want to insure your treasure. Most homeowners policies cover antiques and collections just like any other possession -- subject to normal deductible and coverage limitations. Your policy may cover only the depreciated value, not the replacement cost -- and that can make a big difference with something like antique furniture, which can appreciate with age. Coverage for some items, such as jewelry, is typically limited to a total of $2,000 to $3,000 unless you buy separate coverage for each item. Although items may be covered for fire damage or theft under your general policy, they may not be covered for breakage or theft from a location other than your home. Buying special coverage for certain valuable items eliminates the deductible and adds coverage for breakage, loss or theft if the object disappears when you take it on a road trip. Scheduled items are insured for their appraised value -- the cost to buy the item retail. Plus, some specialty insurers, such as Fireman's Fund and Chubb, may increase the insured value by up to 50% beyond those limits if the value has increased. The cost to cover a piece of art can range from 9 cents to 20 cents per $100 of insured value; coverage for jewelry tends to cost more. Consider buying special coverage for individual items worth $10,000 or more. Or get blanket coverage for an entire fine art collection. You may get a discount if you have a home security system. Part of your object's value is linked to its history, or provenance. Keep detailed records of when you purchased or inherited it, its value at the time, and any other information. Then keep those records, along with photographs of the item, in a safe location, such as in a safe-deposit box at your local bank.