I'm not the most knowledgeable about this, and the practice I'm going to mention is still done today, but... there is a tribe in Africa, the Himba I believe, who use red kaolin clay and smoke to bathe. It gives their hair and skin a beautiful red color. Try looking it up! I've always found this really interesting.
And there's historical paintings of Japanese women bathing and brushing their hair. They seem to roll down parts of their kimono to the waist and wash and comb their hair in a basin...but I'm no historian, I've only seen a few paintings, and no idea what oils or products they might have used.
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