Updated fire, I hope the greens are out now. Otherwise I don't know how they get there (fire is red-orange, followed by brownish-grey colors for higher altitude).
I think you can compare Neanderthals to children maybe; let them play for a day in the bush with a bit of muddy ground and they think they're clean enough to attend dinner. I don't think Neanderthals were as fussy about their (too) perfect appearance as today's people are, and only washed if things itched and they'd happen to cross a stream. And maybe they'll still find the Ivory Soap artifacts!