The Oldest Pyrex Bowl Set Is Also One Of The Most Valuable To Find Secondhand

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While collectors today love Pyrex for its nostalgic patterns spanning charming garlands to whimsical flora and fauna, its earliest baking dishes debuted in 1915 with clear glass (which the brand continues to manufacture and sell today). The introduction of color came in 1945, when the brand released the "world's most famous mixing bowl set" in a line of primary hues. The product was a partnership between the U.S. government and Corning Glass Works to produce a lightweight yet durable dish for soldiers during WWII.

The resulting opal ware glass soon sold to the general consumer, featuring a milky white interior and a colored overlay. The Primary Color set came with four mixing bowls in yellow, green, red, and blue. Today, these OG designs are highly collectible and valuable — an unused set can fetch over $800 on sites like Etsy. Thanks to the brand's signature durability, even well-loved sets can be found in great shape, retailing for anywhere between $100 and $500. Since these are long discontinued, go hunting at your local thrift store: This rare Pyrex bowl may be waiting there.

Made in the 1940s and '50s, primary bowls are a discontinued Pyrex style you can only buy secondhand. In fact, many lack the model numbers on the bottom later used to catalog product runs — don't overlook this sign of value on vintage Pyrex. You should be able to make out "Pyrex" imprinted into the base, whereas later styles will have "Pyrex," "Made in the U.S.A.," and a lot number (typically in the 400s).

If you are lucky enough to find one of these coveted sets at the thrift store, or you decide to splurge on one in a vintage store or online auction site, you will love it for its instantly recognizable Pyrex styling and Midcentury Modern hues. Give your china cabinet a happy injection of bright color, or style it on an open-shelved cabinet. And, don't forget to actually use your Pyrex. Use these mixing bowls as salad servers or to hold sides for your next big holiday. They are still oven safe (just don't heat them above 425 degrees Fahrenheit or place them in the oven directly from the fridge or freezer), so you can bake and serve from the same dish. After, wash with a mild soap and avoid the dishwasher.