
If purging your makeup and skincare stash is one of your decluttering goals, there’s a handy little shortcut you can use that’s right under your nose.
Not all makeup and skincare products, alas, include a clearly visible expiration date. But for those that do, you need to know where to look, because it’s not presented in the format that you’re used to seeing on food (such as Best By: DD/MM/YYYY). However, there’s a tiny, easy-to-miss symbol that tells you what you need to know: the PAO symbol.
PAO stands for Period-After-Opening. This symbol tells you how long you can safely use a product after you’ve opened it. It looks like an open jar with a number on it followed by an “M” for “months.” So a PAO symbol with 6M on it means that the product is good for six months after opening.

This symbol is incredibly useful when going through old makeup and skincare products to see whether they’re still good. Sometimes, a product will look and smell just fine, but will actually be long expired. It’s best to toss those super-old products even if they still look okay, as they may secretly harbor bacteria that can lead to skin problems like acne or (in the case of eye makeup) a bout of pinkeye.
Of course, if a product has changed in color, smell, or consistency since you bought it, it’s definitely expired—but the PAO symbol is helpful when the signs of expiration aren’t so obvious.
The bad news about the PAO symbol is that not every product actually has it. If you don’t have a symbol to work with, you’ll need to consult a guide to general product expiration periods, like this guide from Marie Claire. The other bad news is that this symbol is often tiny. You may have to look very closely to find it, and sometimes it’s so small that it’s actually hard to read the number inside.
But even with those drawbacks in mind, checking for PAO symbols can help a lot when you’re cleaning out your cosmetics collection for the new year. If you’ve never looked for this symbol before, you might be shocked to discover just how many products are past their expiration dates!
For those who use a lot of beauty products, it may help to jot down the date when you first open a new item, especially if it’s something rarely used—like a statement lip color. That way, you’ll be able to tell exactly when it’s reached the PAO date. Keeping your beauty stash fresh and safe for your face is a lot easier if you note the date and follow the PAO guideline.