Pyrex dishes have been a staple in American households for over 100 years.
Even if you don't own any, chances are your parents' and grandparents' cupboards are chock full of the brightly-colored kitchenware.
But little do most people know, the vintage dishes they've been allowing to collect dust for decades might actually be worth a fortune.
However, not all bowls can fetch such a handsome sum.
TODAY reports that opaque, brightly colored pieces that feature floral and geometric designs tend to resell for the highest price.
Pyrex products made between 1915 and the late 1970s are especially sought after in the online market.
According to Bon Appétit, these early dishes were crafted from borosilicate glass, which is the same thermal, shock-resistant material used to create railroad lanterns and industrial glass.
This strong material made the dishes borderline indestructible.
Eventually, Pyrex began using tempered soda-lime opal glass to make its dishes instead of the much-stronger borosilicate glass, a change which made original Pyrex dishes even more valuable and sought after.
A post shared by Hob&Nail (@hobandnail) on Jul 30, 2017 at 5:36pm PDT
Today, the online market for Pyrex dishes is booming.
A quick Instagram search of the hashtag #pyrexforsale reveals nearly 18,000 posts of colorful, vintage glassware available for purchase.
Such bright and cheerful patterns on some of the Pyrex we have in stock at the moment. Link in bio #otherworldvintage #pyrex #jajpyrex #phoenixpyrex #pyrexlove #pyrexforsale #vintage #vintageforsale #retro #retrokitchen #vintagemixingbowls #60skitchen #70skitchen #etsyshop #etsystore #vintageshop #etsyseller #smallbusiness #selfemployed #saturdayvintage #forsaleonetsy
A post shared by Clair Gough (@lucidvintage) on Jul 29, 2017 at 12:05pm PDT
There are even entire Pyrex Facebook groups where collectors sell and swap the coveted dishes.
So the next time you're hitting up your elderly neighbor's garage sale, keep an eye out for these vintage dishes -- they could fetch you a pretty penny.