When we think of expired household products, rotten food and rancid milk usually come to mind. However, many items around the house can go bad with less obvious signs. Some products have expiration dates. Others don’t. Know the signs that indicate your household purchases have gone off — using expired products can lead to some serious health problems.

Toothpaste

Toothpaste contains fluoride, which keeps tooth enamel healthy, but this chemical degrades over time. Two years after production, toothpaste loses its potency. If the taste or color of your toothpaste starts to change, it could be a sign the active ingredient is breaking down and you need to restock. Old, opened tubes can even develop bacteria. To prevent toothpaste from going bad, always put the cap on, and store it in a cool place, preferably a closed cabinet away from other bathroom germs.

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Pillows

Expired pillows are uncomfortable and can become breeding grounds for dust mites. Using an old pillow can also worsen allergies, acne, asthma, and neck pain. Experts recommend replacing pillows every one to two years, though down lasts longer than synthetic. To test if a pillow is still good, fold it in half. If the pillow stays folded, then it’s going bad, and it’s time for a new one. Other signs to look for include smells, lumpiness, and a constant need for fluffling to support your head. To keep a pillow fresh, wash it every three months, but make sure to check the cleaning instructions.

Towels

People tend to keep towels in warm, damp environments, which leads to germs. Washing towels frequently, even with hot water, doesn’t always get rid of all the bacteria that can accumulate on them. The health risks of using old towels include skin irritation and the possibility of breeding infectious diseases. Towels should be replaced every one to three years

Power strips and extension cords

Extension cords don’t tend to have an expiration date, but they can still stop working and become fire hazards. Check for signs of wear, cracks, or damage. Extension cords also become less effective over time. Keep an eye out with old cords. Remember that power strips and extension cords are one of the leading causes of electrical fires in homes.

Medications

While some medicine just loses its potency when it expires, others are dangerous if used past their expiration dates. To be safe, keep an eye on these dates and always read the information that came in the package. If the medicine looks expired — if it’s powdery, smells, or is dry (when a cream or ointment), for example — then it should probably be thrown out. A change in taste or smell could also be a sign. If you’re unsure, speak to a medical professional before using the questionable product.

Makeup

Negative effects of using expired makeup include skin irritation, breakouts, and even eye infections. To slow the expiry of your makeup, always clean your brushes before using them. Washing your face and not sharing products also helps keep makeup uncontaminated. If your makeup smells or has changed color or consistency, its time to replace it. Makeup usually expires within two years, even if left unopened. Eye makeup and products that contain liquid, cream, or oil go bad more quickly.

Cleaning products

Cleaning products last about one to two years after they are opened, less if they have an antibacterial agent. Disinfectant wipes and hand soap have a similar shelf life. They won’t be harmful, per se, after expiring, but they won’t work as well, and if they leave germs behind, this could lead to illness. Lumpiness, a change in color, or a weird smell are signs that a cleaning product is past its time. Consider noting when you bought a product, on the bottom with a permanent marker. This makes it easier to keep track of future expiration.

Sunscreen

Over time, certain ingredients in sunscreen oxidize or degrade, which reduces its potency. Sunscreens stay effective for at least three years, but should not be used after that time frame. Using expired sunscreen can lead to sunburns, rashes, and increased risk of skin cancer. To keep your topical protection working well, keep it out of extreme heat. When outside, put sunscreen in the shade or in a second container. If it smells, starts to separate, or gets watery, it’s time to toss it.

Razors

Disposable razor blades can expire once they are taken out of the package. The metal from the razor oxidizes when it comes in contact with oxygen from air or water, regardless of whether you’re actively using it. Using expired razors is dangerous because the resulting rust can cause infections. To make razors last longer, dry them off with a towel or blow dryer after every use. Also, keep them in a cool and dry place. The bathroom is not the ideal location for a razor since there’s so much heat and humidity. Regardless of how long you’ve used it, if your razor gets dull, throw it out.

Spices

Although usually not bad for your health, some people report stomach pains from eating expired spices, so better safe than sorry. The main problem with using old spices is that they lose their flavor over time. To tell if a spice has gone bad, smell it. If the scent is strong and familiar, then it’s probably still good. If you have to stick your nose right in it to pick up on any aroma, toss it.