Using expired makeup is gross, yet we are all guilty of doing it at some point. And unfortunately, all makeup is not created equal. Some items like mascara will last only 3 to 6 months, and others like powder eyeshadows are fine for years. But what happens to your skin when you take that risk? And how do you know if your makeup is beyond its time?

You might think that just because nothing smells weird, it is fine, but that is not always the case. Some things are less potent after a beauty product expires, but others can cause acne, rashes, or worse. So, staying on top of the freshness of your makeup is just as important as the food you eat.

The first step to protecting yourself from old makeup happens at the time of purchase. You may think your mascara or foundation is fresh because you just picked it up. But whether you shop at Sephora, Bloomingdale’s, or your local pharmacy, that makeup could be sitting around for ages. And those who stock the shelves are not always on top of clearing out old products. There have been recent sightings of separating and even moldy makeup at popular drugstores. So keep your eyes peeled because this is not just old. It is archaic.

If your makeup looks just fine and is yet to be open, you might think that makeup is perfectly safe to use, but just like canned goods, everything has an expiration date. But how do you figure out what it is?

Almost every product from luxury to Wet n Wild has a batch code printed somewhere on the container. This code tells you when the product was manufactured. Websites like checkfresh.com and checkcosmetic.net show examples of where you can find these codes on your products. From there, you choose the brand and type in the code. The website will then let you know when that product was made.

If the date you receive is within the last three to five years, you should be safe. But with that being said, once a product is open, that time is no longer relevant. Printed on the packaging of many products is a symbol of an open container with a number in it. That number tells you how many months your product is good for once it is open. Once a beauty product is exposed to the air, it can breed bacteria, so the time is cut down.

Most new products you buy should have been manufactured well within or well under the three to five-year recommendation. But sometimes, retailers fall short of this. For instance, TJ Maxx for selling expired makeup and skincare. This is most likely to happen when buying things on sale or discounted, but sometimes even full-price items are old. So it is always good to check.

This is not a foolproof method as some brands recycle their batch codes, and the websites have not been updated to reflect this. So you might purchase a mascara that just launched, but the batch code could reveal it was manufactured five years ago. That would be a recycled code. So along with this method, keep your common sense at the forefront for situations like this. But when you come across a deal that seems too good to be true, it very well, maybe. So always check if you are shopping from clearance or during a major sale. You might be surprised at what you find out.

There are hundreds of charts online to guide you through what expired means for each type of beauty product. And for the most part, you can trust them. Products like mascara can only be stretched as far as six months. And it is essential to stay on top of this when it comes to products you use around your eye area because you could get a severe infection. Eyeliners last longer because by sharpening them, you are removing the top layer. Then, most powders last much longer because they have less of a chance of growing bacteria. Liquid and cream products tend not to be good after a year or so, and as they go directly on the skin, they can cause serious reactions if used after their recommended shelf life.

But always use your common sense. Things like eyeshadow palettes can last a long time if you keep them clean with an alcohol spray. But old lipsticks can start to grow fuzz on them. And if any of your products start to smell or change color, it is time to toss them; no exceptions.

It can be frustrating to get rid of makeup and beauty products because you invest in them and may even have an emotional connection to certain items. But your health is the most important. And if you can’t seem to put your health above your love for beauty, remember that using old makeup can cause severe allergic reactions, rashes, and acne.

If you want to avoid letting products go bad under your watch, stay on top of it. Every couple of months, go through your beauty collection and shuffle things around. Move things you haven’t used in a while to the front, so they get some face time. You can also donate anything that has not been used to women’s shelters. Project Beauty Share was started precisely, for this reason, to donate to women in need. You can check out their website for more information on what is acceptable and where you can donate your items. Or offer products you didn’t like to friends and family, as long as they are sanitary.

Sadly makeup does not last forever, but you can make the best of the time you have with your favorite beauty products. Just be sure to say goodbye to them when the time is right.