The novel made fun of them, but heck, now we're putting kaolin clay in gauze!
As an aside, the diarrhea medication Kaopectate (and other brands) used to use kaolin clay as their primary ingredient, so many of us have been benefitting from using clay for a long time. Kaolin was phased out of all of those meds back in the 90's IIRC, but most brands retained the "kao" brand names.