This will make beauty gurus bristle.

Let’s face it: Hairbrushes get dirty. With every rake, the bristles are quickly enveloped in hair, product and other scalp debris that mimic the appearance of “dust bunnies” that you might see on shelves, books and windowsills.

California cosmetologist Casey Davis is warning the long-haired beauties of TikTok to wash their hairbrushes twice a month, or more, to avoid nasty bristle build-up.

“Those little dust bunnies — you know, these bad boys that you see,” she said in a video with more than 3 million views this month, gesturing to her own black hairbrush covered in hair and fuzz.

“These little dust bunnies are actually dead skin cells and oil buildup,” she continued. “Ew.”

She advises bi-monthly cleans in a sink or tub of some sort, using hot water, clarifying shampoo, a pinch of baking soda and an old toothbrush to rid the brush of built-up crud.

After removing the excess hair clinging to the bristles, she instructed her followers to scrub the hairbrush and let it soak for 30 minutes.

The Post has reached out to Davis for comment.

The viral video is part of the content creator’s healthy hair series that features her tips for maintaining a shiny, think mane.

In other clips, she recommends shampooing twice in one shower, refraining from applying conditioner to the scalp, using an oil treatment, and washing hair in cooler water for scalp health.

After all, she argues in one caption, “Healthy hair comes from healthy scalp.”

Other hair conscious creators have shared their hair-raising brush cleaning routines on TikTok.

“The only reason that you should have to clean your hairbrush is to minimize parasites and excessive amounts of bacteria or fungus living on your hairbrush,” William Gaunitz, a certified trichologist, told Shape.

“If you have an excessively oily scalp and/or any scalp condition, such as dandruff or itchy scalp, you may be experiencing an overgrowth of bacteria or fungus,” Gaunitz added.

More frequent hairbrush maintenance may be necessary in that case because “you could easily continue to re-infect your hair and scalp every time you use your hairbrush with whatever is living on your hairbrush.”