Some Oceanic musical instruments served a dual function. The Iatmul people of the Middle Sepik River region in northeast New Guinea use betel nut—areca palm fruit, which is chewed with lime made from burnt shells or coral and other substances as a mild stimulant. Among the Iatmul, the ornate containers and spatulas used respectively to hold and serve lime served as both betel nut–chewing accessories and noisemakers.
In the past, Iatmul culture valued the qualities of aggressiveness and assertiveness in men, and individuals used their lime spatulas and containers as rasps to emphasize these traits audibly. The tops of lime containers had a hole for inserting the spatula while the lower end of the spatula was carved with a series of ridges. When a man wished to call attention to himself in social situations, he rapidly thrust the spatula in and out of the lime container so that the ridges, rubbing against the edges of the hole, produced a harsh rasping noise that served as the audible expression of his pride, assertiveness, or displeasure.