About nine months ago I persuaded her to try absolutely nothing. Just wash her face with mild soap and water when she showers or after exercise. It was a hard sell. A really hard sell. It looked sinfully angry for the first few weeks, and then, bit by bit, started to fade.

Now... her skin is perfect, the scars are subsiding, and she hasn’t had even a hint of acne or so much as a zit in four months.

The crux of my hypothesis was that she was eradicating her skin microbiome over and over, and possibly breeding incredibly resistant bacteria with no competition.

I take a similar approach with oral hygiene - I don’t brush, I don’t use toothpaste or mouthwash, I just use a wooden toothpick to get anything stuck out. I started this in my teens at boarding school, as toothbrushes were often “borrowed” for cleaning rugby boots, and then replaced in the rack. At the time, I figured not brushing was better than god only knows what being rubbed into my gums. I had appalling breath and swollen gums for several months - but both just disappeared after adaptation.

I go to see a dentist every few years, mostly out of a sense of obligation, and have never had a carie, cavity, periodontal disease, or anything - I’m pushing 40. The most they’ve ever done is polish them. By my age my mother had lost half her molars, my father had a gobful of crowns and fillings, so it’s not genetics.

Maybe I’m talking crap, but I think we significantly underestimate our bodies abilities to maintain themselves, and buy into the idea that we require products to keep them working.

Unfortunately, weaning yourself off this stuff usually involves some degree of disruption, be it honking breath, or skin so angry you don’t want to be seen in public.