"Soap? What's soap?"
Humans have been making soap since the Mesolithic. It's literally just fat or oil mixed with ashes; but we're supposed to believe that in a city that's obviously early industrial era, they've never heard of soap.
Also, soap isn't that good for your skin. It strips it of moisture and destroys the proper bacterial balance allowing pimple causing bacteria like Cutibacterium acnes to flourish.