Every morning, it stares back at you, its contents overflowing. You’ve been dreading this all winter, but in the spirit of spring cleaning, you decide to bite the bullet. It’s time to clean out your makeup bag.

You are stunned by what you find lining the bottom of the bag: Pencil shavings, foundation powder, melted lipstick, matted brushes, leaky mascara — it’s like something out of a horror film.

Don’t worry, you’re not alone, says Adi Lando, pro beauty team artist at Sephora. “When women come to my store, I always see a disaster — they’ve sharpened their pencils inside the bag!” he says, aghast.

According to Nicole Clark, beauty boutique co-ordinator at Shoppers Drug Mart, you should clean your makeup bag every season. “You’re updating your look anyway,” she says, “and you keep all of your products fresh that way.”

If you’re not sure how old your makeup is, check the bottom of the jar, Clark says. There’s a symbol of an open jar on the bottom of the packaging with a number: This gives you the product’s shelf life in months from the time you opened it.

“If your makeup changes texture or has a funny smell, throw it out,” Clark says. “Err on the side of caution.”

Lando agrees. “The best way to find out if makeup is old is to do the sniff test, especially with foundations,” he says. “If it smells bad, you definitely don’t want to use it.”

And if you can’t remember when you bought it, toss it, he says.

You should throw away old makeup because it affects the product’s performance, says Clark, adding: “The pigment might fade or change a bit.” Also, because skin absorbs makeup, any bacteria on old makeup can cause an infection or irritate your skin.

One item you should change every three months is your mascara because the dark, wet tube is the perfect environment for bacteria to grow in, Clark says. “Because it’s near your eyes, you want to be extra careful,” she says.

According to Lando, you should replace your foundation every six to 12 months, or after six months if it starts to separate or smell. Replace your eyeshadows every few years because there’s no water in them, he says, adding: “If you’re worried about it, scrape off the first layer and then use it.”

As for lipsticks, they should be replaced every two years. “But if you’re worried about it,” Lando says, “clean the tip with alcohol, or shave off the first layer.”

Lip and eye pencils last as long as you sharpen them, Lando says, adding: “I don’t know what’s with women and sharpeners! How can you use it if you don’t sharpen it?”

Once you’ve cleaned out your makeup bag, don’t forget to clean your brushes. “You should clean your brushes before you put them back, and do it on a regular basis,” says Lando, who recommends you clean your foundation brushes every day. He suggests using wipes to clean your brushes if you don’t have time to wash them. If you do have a bit more time, use baby shampoo to clean brushes made with real hair, and something alcohol-based to clean your synthetic brushes.

Clark agrees. “When you’re using makeup brushes, wash them frequently,” she says. “Clean your brushes once a week.”

Clark recommends using a Quo brush cleaner with tea tree oil; you just spray it on your brushes, and rinse it off.