If your jewelry box is a tangle of bling you no longer wear, you may be able to turn those baubles into a car payment, a vacation, a bathroom remodel — whatever you value.

To get the most out of your unwanted jewelry, you need to know what the jewelry is worth and where you should sell it. You also need to know yourself. “How much effort do you want to put into selling your jewelry?” asked Martin Fuller of Martin Fuller Appraisals in McLean, Va., who is a master gemologist and senior accredited appraiser. “It’s a balance of what your time is worth and what you might recoup selling your jewelry.”

To truly know the value of what you are selling, you should get an appraisal by a member of the American Society of Appraisers, the International Society of Appraisers or the National Association of Jewelry Appraisers. Members of all three groups have to adhere to standards and ethics. Appraisals range from $150 to $350 per hour. To give you an idea, a simple diamond ring might take about an hour to appraise, whereas one with multiple diamonds and an elaborate setting might take more than three hours. Some appraisers charge by the item, but under no circumstances should an appraiser charge you a percentage of the item’s value.

Some people reason that they can skip the appraisal if they believe their jewelry isn’t worth much. If you are absolutely certain what you have is not valuable, you can go ahead and seek offers for it, but beware. “I have many times taken very expensive jewelry out of a client’s “costume” pile and moved it into their fine jewelry pile,” Fuller said. One time a client brought Fuller a sapphire with an old appraisal attached that claimed it was worth $18,000. Fuller noticed some unusual characteristics under his microscope and recommended advanced testing. Turns out it was a rare, untreated Kashmir sapphire worth nearly half a million dollars!

An appraiser can also tell you whether your jewelry is best sold as-is or for scrap. Some jewelry by well-known designers is more valuable intact.

Once you have your appraisal in hand, keep in mind that you are unlikely to get that price. Appraisals, often conducted for insurance purposes, determine the retail replacement cost of your jewelry, not the resale price. So ask your appraiser whether he or she can give you a resale price estimate as well. With gold jewelry, an appraiser may tell you the “melt” price of your piece, which is the value of the precious metal contained in it. Again, you are unlikely to get this price, because the buyer must factor in his own profit margin and the cost of extracting the gold. Experts say that if you can get 70 to 80 percent of the melt value for your gold, that is a fair price.

Use caution if you want to sell your jewelry online. The Better Business Bureau receives a lot of complaints about online buyers who offer lowball prices, fail to return jewelry if you reject their offer, or don’t send payment for your items. I once collaborated with a master gemologist appraiser and sent exactly $350 worth of gold to three different online gold buyers. One offered us $206, another $90 and a third $66. When we rejected these offers, some of the companies then made us better ones. This experiment shows the value of shopping around for the best offer and declining the initial offer. A website called Where2SellGold.com has done similar experiments, with similar results.