sentences:  The Ibo tribe still used them prior to this and at Wukai a deep bowl of corn was considered equal to one large "manilla" and a cup-shaped receptacle filled with salt was worth one small "manilla".Although manillas were legal tender, they floated against British and French West African currencies and the palm-oil trading companies manipulated their value to advantage during the market season.The British undertook a major recall dubbed "operation manilla" in 1948 to replace them with British West African currency.