Dancers also often place a "chundanga seed" (variety of eggplant which bears small fruits) under their lower eyelid before the performance to turn the white of their eyes red. In fact the "chundanga" is not really a seed and is prepared by removing the ovaries at the base of the flowers of this plant. The procedure used for preparing these seeds involves the rubbing of a bunch of these in your palm until they become black (starting from a white color) and nearly dehydrated. They often last long enough for a season (of around four months) in this condition.
https://en.wikipedia.org/wiki/Kathakali