There could be cash in your kitchen cabinet.

People are just discovering that their vintage Pyrex, a hard heat-resistant type of glass that’s extremely durable and microwavable, is selling for up to $1,800 online with single mixing bowls going for around $900 each.

Ever since the coveted dishware changed its formula to soda-lime glass instead of the much stronger borosilicate, the discontinued Pyrex became more valuable than ever with pieces from 1915 to the 1970s becoming highly sought after all over Instagram.

“It’s a wonderful product. You can microwave it, they don’t break they’re fantastic,” Paul Anavian, managing director at the Manhattan Art and Antiques Center tells Moneyish.

“It’s going up in price because all of the sudden they’re not making them anymore. They have these lovely colors. It’s almost an artistic thing.”

The bright-colored bowls are popping up all over social media with collectors buying and selling the old glassware using the hashtag #pyrexjunkie, which shows more than 12,000 posts.

And many of the posts are from millennials, who, in an age of Ikea, minimalism and anti-clutter, are looking to purge their parent’s “junk,” and make a few bucks doing it.

Anavian says if you don’t have any Pyrex laying around, you could very well stumble upon other items like porcelain or silver found on plates, knives and cocktail shakers. Or, if you’re really lucky, perhaps some crystal wine glasses.Here’s what to look out for:

Cocktail Shakers:

Your favorite martini shaker could double as quite the money maker.

Authentic silver plated cocktail shakers are selling for $130 to $450 for vintage brands like Bruford Eastbourne on Etsy.com.

Flip over the shaker to see if it’s branded to find out how much its worth, but if not, you can test its authenticity by using a strong magnet. If it sticks to the piece, it’s not real silver.

Dishware:

Porcelain dishes handed down from your grandmother could go for $25 to $30 per plate to a few hundred bucks, says Anavian.

A pattern or design on white translucent ceramic china could be an initial clue that your dish is porcelain, and might be worth something.

Check the back of the dish or bowl to see if there’s a symbol on it with a region where it’s from and simply Google its worth.

One of the highest qualities around is Meissen, for example, the German company that’s been making porcelain since 1710. It features two crossed swords on the back of its china and prices go from $70 to $600 on Estsy.

Knives:

One sharp sign you have a good knife on your hands is the blade hardness. A blade’s hardness is controlled by the grade of steel that was used during the crafting process.

Sets of silver handled knives could be worth an estimated $100 to $200, according to invaluable.com.

Cast iron cookware:

Vintage cast iron enamel cooking pans made of iron can go for $70 and up.

Some sellers are digging up old vintage Le Creuset pans from the 1980s and getting up to $450 for a set of five.

Single sellers, like Dutch ovens, complete with chrome handles that can be used in the stove or in the oven go for around $160.

Baccarat crystal:

Baccarat crystal dates back to before the 19th century with everything from fancy perfume bottles to barware and even paperweights.

In most pieces, the company name is carved into the crystal, but earlier ones may simply have the letter “B” and the year it was made.

A pair of wine glasses are selling for $95 on Etsy, but vintage French crystal glasses can go for upwards of $3,000.