Djerrk are primarily made from the bark of Baḻgurr (Red-flowered Kurrajong - Brachychiton megaphyllus) but sometimes Banyan tree (Ficus virens) and Cocky Apple tree (Planchonia careya). Sections of the tree are cut, and depending on the size, whole portions or part portions from the trunk. The inner bark is beaten or chewed to soften then dyed with natural bush dyes. Once softened and dyed, parts of the fibre are separated into fine strips then rolled on the thigh to create a rope otherwise known as bush string. The bush string is then woven and knotted to create a djerrk (string bag). Djerrk were used for every day utilitarian purposes, particularly collecting bush foods such as bäḻtji (yam).