A lumpy yellow pillow with mysterious stains has become a staple in one too many homes, according to heated online conversations that attempt to make sense of the strange obsession.

“If you don’t have a crusty yellow pillow, you have never lived,” goes one TikTok comment. “There’s no pillow like old yellow,” another reads. 

A recent tweet that called yellow pillows “magic” has received loads of likes, and even garnered the attention of NBC News, but people have been sharing videos about their beloved yet terribly stained mush of cotton for years.

As much comfort as you think your yellow pillow brings you, however, it’s time to say goodbye. All that discoloration, experts say, is an accumulation of grime that can pose problems for respiratory, skin and sleep health.

“These old yellow stinky pillows, while there is some type of emotional attachment to them, are exposing you to allergens and creating a breeding ground for mold,” said Dr. Zachary Rubin, a pediatric allergist in Illinois. “Plus, as these pillows wear off over time, they don't give you the kind of neck support that you need.”

Why your pillow is yellow

The accumulation of oil, dirt and sweat from your hair and skin over time leaves a grimy residue on your pillow that leads to discoloration, said Dr. Lindsey Zubritsky, a dermatologist in Mississippi. 

Your face also produces a sticky oily substance called sebum that keeps your skin moisturized. Sebum differs from sweat, but it collects on your pillow just the same. 

Drool, makeup and other face products, and wet hair can also make your pillow yellow, Zubritsky said. 

Why your yellow pillow could be a health hazard

Sleeping on your favorite yellow pillow for years on end can lead to acne breakouts and other types of skin irritation because the buildup of dirt can clog your pores, Zubritsky said. This is especially true for people with eczema, rosacea, existing acne or otherwise sensitive skin. 

Perhaps more problematic for some people is exposure to allergens that like to call your yellow pillow home, namely dust mites, Rubin said. 

Dust mites are microscopic bugs that like to eat tiny flakes of dead human skin. When you sleep on a dirty pillow, you are likely inhaling proteins from their poop, urine or decaying bodies, which can inflame and irritate your airways. 

“Dust mites thrive in humidity, so you’re essentially sleeping with a major allergen,” Rubin said. 

About 4 out of 5 homes in the U.S. have dust mite allergens in at least one bed, according to the American Lung Association. The critters are a major indoor trigger for people with asthma, and can live in upholstered furniture, carpets and curtains too. 

Your immune system has a circadian rhythm, Rubin said, meaning certain conditions like allergies, eczema and asthma flare up on unique schedules according to the time of day, but mostly at night. If you have a dirty pillow, you’re likely aggravating those conditions even more when you’re trying to rest. 

Poor sleep can lead to a host of health issues, such as chronic fatigue, stress, high blood pressure, depression and increased risks of infection. 

Mold and pet dander are other irritants that can accumulate on your pillow, Rubin added.

How to keep up with pillow hygiene

The first step in keeping your pillows clean is to avoid sleeping on them without a pillowcase. Certain pillow cases are more gentle on skin and may discourage bacterial growth, she added, such as those made of bamboo and silk. 

You can also buy a zippered covering that can be washed and goes in between your pillow and pillowcase for added protection, Rubin said. 

How to properly clean and disinfect pillows:

• Remove pillowcases and sprinkle baking soda over your pillow to reduce odors.
• Vacuum the baking soda after at least 30 minutes.
• Spray your pillow with a fabric-safe sanitizer.
• Air pillows outside for a few hours every two weeks.
• Machine wash pillows in a delicate cycle every three months, preferably with detergents that are free of fragrances, perfumes or dyes.
• Air dry before replacing the pillowcase.
• Replace your pillows every one to two years.

These tips differ depending on the type of pillow you own, so read any labels before washing.