Have you ever noticed a strange smell develop in an old bottle of moisturizer or cleanser? Or, when you squeezed the product into your palm, it looked a bit clumpy and discolored? When this happens, throw the bottle away immediately! Your product might have grown mold. Gross.

In an interview with Allure, Joshua Zeichner, the director of cosmetic and clinical research in dermatology at Mount Sinai Hospital in New York City, said that many skincare products contain preservatives to prevent microorganisms like bacteria, yeast, and mold from contaminating and growing inside the products. However, these preservatives aren’t always 100 percent able to defend against fungus.

Mold needs moisture, warmth, and food to grow, according to Miami Beach, Florida dermatologist Roberta Del Campo. Products are more likely to grow mold when stored in hot, humid places. To avoid mold, store your skincare products in dry, cool, dark places and keep an eye on the expiration date. Some brands will indicate on the packaging how long a product will be good for once opened. Other brands use a coding system with letters and numbers to tell the date of manufacture. Keep the lids on your products tightly closed to avoid moisture getting inside.

Mold isn’t always easy to spot—sometimes it will blend with the color of your product, so relying only on sight to tell you if the product is still good won’t always be enough. Some users find it best to decant products into clear glass bottles to see the product before putting it anywhere near skin. If it doesn’t smell or feel like it did when you purchased the product, throw it out to be better safe than sorry. A change in smell is often the biggest indication of mold growth in skincare products.

Fungus can cause skin irritation depending on the current state of your skin. According to Ted Lain, a dermatologist in Texas, those with normal immune systems and few irritation or inflammation problems on their skin are less likely to see serious problems when exposed to mold. However, it could cause an infection in those with compromised immune systems. Mold can cause rashes, hives, swelling, and itching in less severe cases.

An easy way to keep your products safe from mold is to keep them refrigerated. A mini-cooler for your skincare products might be a good investment for storing them wherever you conduct your skincare routine—Rihanna’s makeup artist Priscilla Ono has one!

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Beauty & Wellness Tips From Marilyn Monroe's Archives
Beauty & Wellness Tips From Marilyn Monroe's Archives
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