When it comes to beauty industry ingredients, clay is nothing new.
As well as being used to fashion pots and crockery, the sludgy stuff has been part of skincare regimes for thousands of years, dating back to Roman spas. Roman author Pliny the Elder wrote a whole chapter about the benefits of clay in his The Natural History, including treating blackheads and acne.
It’s quite remarkable, then, that the historic healing substance is helping address some very modern skin concerns.
"Clay acts almost like a magnet, and really draws everything out from underneath the skin," says Sarah Inomata, skincare expert and international sales executive at boscia, the brand famous for its peel-off Luminizing Black Charcoal Mask, which combines the purifying powers of clay and charcoal.
"The main clay that we use is the calcium montmorillonite clay, sourced in France. It’s also known as bentonite clay and contains 67 different types of minerals – that’s what really digs deep into the pores."
By leaving the mask on until it dries (about 20 minutes), then peeling it off, it takes with it many of the nasties that get under the skin’s surface on a daily basis – both visible and invisible.
"Extra sweat, pollution… we’re all a little bit more oily, especially in the summertime, and in the city there’s a lot of pollution and smog that accumulates throughout the day.
"So this is something that, if you add it into your regular routine, really does help maintain that skin health, but also helps minimise visible pores."
But unlike harsh acids or scrubs, clay products are gentle enough to be used even on sensitive skin.
"That’s why clays are so popular, especially in a mask format," Inomata says, "because they’re applied quickly and they’re so powerful, but not in a harsh way."
She recommends using a clay mask a couple of times a week, then you can ‘top up’ with a clay cleanser for daily use if you have oily skin. "It’s a less potent formula if it’s in a cleanser. So do your mask once or twice a week to get a deep clean, and then use your cleanser every day. You don’t want to ‘over-clay’."
Feat of clay: 7 purifying products to try now
Boscia Luminizing Black Mask, €34.99, Boots
Dr. Roebuck’s Uluru Purifying Mask, £25, SpaceNK
Green People No. 1 Exfoliating Face Scrub for Men, £13.50
Face Gym Brazilian Pink Clay Training Stick, £38.50
Seed To Skin The Divine Cleanse Dual Detox Marine Clay Cleansing Gel, €89, Liberty
Men-U 3 Minute D-TOX, €20.45, Look Fantastic
Nivea Shower Clay with Ginger & Basil, €1.62, Boots