This dirty secret is the key to clean jeans.

Charles Bergh, the CEO of Levi Stauss, has admitted he hasn’t washed his denim in a decade, arguing that it’s the best way to care for your jeans.

“I never put my denim into the washing machine,” he previously told CNBCexplaining that denim production and consumers cleaning their jeans requires massive amounts of water.

However, he clarified that his pants aren’t dirty — if he gets a stain he’ll “spot-clean it,” of course — but noted that Americans shouldn’t be throwing their jeans into the washing machine after every wear.

Instead, the Levi CEO hops in the shower fully clothed to cleanse his clothes.

“And if they get really gross you know, if I’ve been out sweating or something and they get really gross, I’ll wash them in the shower,” he continued.

“I’ll just hop in the shower and soak myself down and wash them like that.”

Other “denim heads,” as Bergh calls them, commented on the clip, arguing that they, too, rarely washed their jeans — some as little as once a month.

The denim company recommends washing denim after 10 wears unless they’re dirty or smelly, since “over-washing can ruin the unique characteristics of your jeans.”

When you do wash your jeans, make sure they are turned inside out with the zippers and buttons fastened and washed with like colors in cold water sans-softener.

Jeans should never be put in the dryer, a blog post on Levi’s website warns, since “air drying helps preserve the fit, color and fabric.”

“The sheer amount of water that they are exposed to in a washing machine can be the culprit for affecting the look and color of the denim by fading over time,” John Reid, the managing director at Garment Quarter, told Yahoo News.

“Cotton-based denim jeans with little stretch to them will become more comfortable over time.”

But denim made from mixed materials like elastane can benefit from more regular washes since it could “help the fabric to shrink back down after being stretched due to wear.”

Some jean lovers swear by putting their denim in the freezer, claiming that it eliminates odor and kills bacteria.

Experts, however, say it isn’t a proper substitute for washing.

“The idea is that the freezer kills the bacteria in the jeans and gets rid of the odor,” George Chan, a technical services officer at RMIT University’s School of Fashion and Textiles, told The Guardian. “It might work when you first take them out but it won’t be ongoing.”