In the early 20th century, your problem was straight hair; your fix was sitting motionless for roughly ten hours under 60 pounds of scalding brass irons hanging half an inch from your scalp.
First, the hair was treated with sodium hydroxide (a lye used today in relaxers and drain cleaner to dissolve, among other things, hair), making it softer (or weaker) then heated with two-pound brass rollers, which were suspended with a set of counter-weights to avoid searing the client (with mixed results).
“Almost all of them got burned slightly.”
The madness of crowds finally swept up middle-class women and under the cranial frying pan when Nestle managed to demonstrate publicly that he could perm a volunteer without seriously injuring her.
In 1915, he opened a wildly successful salon chain across America and tweaked the device with safer affordable versions, albeit with the occasional burn victim, and by 1928 he was said to have had amassed a $3 million fortune ($44 million/£33 million today).
A 1946 San Francisco Examiner piece titled “Swindler’s Harvest: Danger at the Doorbell” reported that “[i]n one community alone, a squad of salesmen took in $8,000 [over $100,000/£75,740 today] before they were chased out.” Whether or not that’s true, Weird Universe’s Alex Boese hunted down the contraption’s fate: a 1947 national exhibition of quack devices assembled by the American Medical Association, which even cited doctors’ claims that the dimple-maker may cause cancer.