If you think something is worth money, chances are it isn’t. If you think something is worthless, there’s a possibility it may not be. Old magazines, postcards, and even vintage cereal boxes are among the items people think are worthless but can actually have value

When downsizing, make sure you don’t get rid of valuable items, the best advice is to do your homework. There are a lot of resources out there such as the Internet, antique and art appraisers, and books. So check to make sure you have an idea what something is worth before you relegate it to the trash.

If you have something that’s been in the family a long time, you may want to have it checked out. Send a photo to your local auction house. The auction house should give you feedback about whether it’s worth auctioning or not.

Larger cities usually have qualified specialists working for established companies. What you want to avoid is someone who comes in and scoops up that da Vinci in the basement, before you know what’s happening.

However, be prepared for the negative too. The value of most household goods has depreciated. The next generation doesn’t collect like the last one. Millennia’s are not collecting figurines or traditional furniture. That said, there are collectors for just about everything, antique, vintage, new and everything in between.

Here are some of the top kids’ items with money-making potential that collectors tell parents to look out for when cleaning house:

ACTION COMICS No. 1: This is the most valuable comic ever created, both financially and culturally. Before this comic existed there were NO cape and boots superheroes. Can you imagine that? That’s like two guys sitting down and inventing a color. The concept was so weird that Superman couldn’t even fly for the first couple of years.

Pokemon: Pokemon Go may have taken the world by storm this summer, but there’s plenty of money to be made from the original Pokemon for Nintendo Game Boy. Original game cartridges in good condition are selling to collectors for a few hundred dollars.

Polly Pocket: These tiny dolls and playsets that were popular in the early ‘90s can fetch $500 or more if they’re in top condition.

Furbies: Launched in 1998, these strange owl-like robotic creatures are still highly sought after. Collectors will pay about $600 for one of these guys in mint condition – sometimes even higher if it’s in the original packaging.

Harry Potter: If you happened to get on the Harry Potter train early and bought a 1998 first edition of the first book in the fantastically popular series – Harry Potter and the Philosopher’s Stone – you could be in for a payday. Copies in great condition are currently selling for about $6,500 each. Add a signature from author J.K. Rowling and the price more than doubles to about $15,000.

LEGO: Some LEGO sets and mini figures can sell for hundreds of dollars to the right collector. Before getting rid of any LEGOS, it’s a good idea to check online to see what’s hot on the collectibles market.

If you have the time and the inclination, you can search for items on the Internet to get an idea of their worth. Consignment shops, selling items online and garage sales are ways to cash in on your unwanted items. But you have to gauge whether the time spent will be worth it.

When they are downsizing, people typically make three piles – keep, donate and toss. Adding a fourth pile could make good financial sense.