Beanie Babies were a hot commodity in the 1990s. People spent millions on the pellet-filled toys at their peak, and some even went as far as to forge checks and burgle toy distributors to fill out their collections. So-called “Beanie Mania” was driven by the idea that the stuffed animals would grow in value over time—a gamble that led to disappointment for many owners. But while the majority of Beanie Babies sold decades ago aren’t worth much money today, a select few are worth a small fortune.

According to Dr. Lori Verderame, an antiques appraiser with an expertise in Beanie Babies who spoke with us for this article, some Beanie Babies sell for thousands of dollars. Before you list your childhood toys on eBay, it helps to know if you’re sitting on a gold mine or thrift store material. We spoke with Dr. Lori about what to look for after taking your Beanie Baby collection out of storage and how to potentially make some money from it.

1. Learn Beanie Baby terminology.

Beanie Baby collectors and appraisers have their own language. When researching what makes certain toys valuable, it helps to be familiar with these terms so you can apply them to objects in your own collection. For instance, certain errors or variations of the heart-shaped tag on a Beanie Baby’s ear could dictate its worth. Experts refer to this as the hang tag, the swing tag, or just the ear tag. The looped fabric tag stitched to the Beanie Baby’s bottom end is known as the tush tag, and it can also contain errors that may increase your doll’s value. The “beans” inside a Beanie Baby are called pellets. They come in two types: polyethylene (PE) pellets and polyvinylchloride (PVC) pellets, with PVC being the rarer of the variations.

2. Beanie Baby Errors don’t always make it valuable.

Many of the most valuable Beanie Babies today have some sort of error, either on the tags or on the doll itself. The rarity of these errors can make an otherwise worthless toy extremely valuable to collectors, but this isn’t always the case. “People are surprised to learn that errors are in fact very common,” Dr. Lori says. “They will say, ‘well, mine has an error, so that must be rare.’ They don’t look at enough Beanie Babies to realize that many of them have errors.” If you find a misprint on a Beanie Baby tag or some other manufacturing mistake, do some research before getting your hopes up. Some Valentino bears had up to four manufacturing errors, including brown noses instead of black ones and tag typos, and that place them among the most sought-after Beanie Babies today.

3. Beanie Baby smell is just as important as appearance.

5-Year-Old Adam Kalina's arms are full of Beanie Babies on a 1999 shopping trip with his mother.Bill Greenblatt/Hulton Archive/Getty Images

You may have a rare type of Beanie Baby from the early 1990s with a mint-condition ear tag, but if it smells like your basement, you’ll have a hard time selling it. Mold, mildew, and cigarette smoke can all taint your Beanie Babies with hard-to-remove scents. To prevent this, Dr. Lori recommends moving them out of their cardboard boxes and storing them in plastic containers. “Make sure you’re keeping them in plastic tubs, or even plastic Ziploc bags in order to keep any kind of dirt or damage away from them.” And if you’re a buyer, the importance of odor is a good reason to avoid purchasing vintage Beanie Babies online that you can’t see or touch first.

4. Look for the original nine Beanie Babies.

When appraising Beanie Baby collections, Dr. Lori looks for nine toys in particular. These are the “original nine,” or the first-ever Beanie Babies produced in small batches in late 1993. They include Patti the platypus, Spot the dog, Squealer the pig, Brownie the bear, Chocolate the moose, Pinchers the lobster, Splash the killer whale, Legs the frog, and Flash the dolphin. Even without errors, one of these Beanie Babies will almost always get the attention of toy collectors if it’s in good condition.

5. Be skeptical of Beanie Baby price guides.

Though you can look up how much certain Beanie Babies have sold for in the past, that doesn’t mean every toy like it is worth the same amount. Price guides may claim to know how much every type of Beanie Baby is worth, but these estimations are far from precise. If you want to know how much an individual item could be worth, you need to have it examined by an expert. A Beanie Baby appraiser can not only tell you if your toy is worth selling, but they can help you identify the type of buyer who will be willing to pay the most for it. “Some Beanie Babies need to be properly marketed in certain ways,” Dr. Lori says. “Do you want to market to toy collectors, market to the folks who are only collecting rare Beanie Babies, or do you want to market to someone who says ‘I’ve lost this childhood toy’? There are so many collectors who are still actively collecting them even 30 years past the 1990s, when they were at their height.”

6. Never ship a Beanie Baby that hasn’t been sold.

The wives of PGA Tour golfers sell stuffed Beanie Babies to raise money for charity at the 2004 PGA Tour John Deere Classic.A. Messerschmidt/WireImage via Getty Images

A legitimate appraiser can help you sell your Beanie Baby, but not everyone claiming to be an expert online should be trusted. A major red flag is when someone asks you to ship your Beanie Baby to them in order to get it evaluated. “You should never send your object away to anybody for any reason,” Dr. Lori says. “People send them away and never see the object again. [Scammers] say, ‘Oh, I lost it. It never got here.' No expert who is worth their weight will ever want your object.” The same goes for potential buyers who haven't put any money down on your item yet.

A much safer way to get a toy evaluated is to do it through a video call. Many professional appraisers are willing to do this, and it's still an accurate way to gauge your Beanie Baby’s worth compared to showing it to someone in person.