Sheepskins with wool intact are classified as raw or dressed furskins, not as leather, because the primary commercial value lies in the wool or fleece rather than the hide. Removing the wool before or during tanning shifts the product into the leather classification. Importers should ensure supplier documentation explicitly confirms the wool-off condition to avoid misclassification at entry.

Initial tanning stabilizes the hide against putrefaction. Retanning — applying a second tanning agent after the primary tan — modifies the leather's temper, fullness, and surface character without constituting 'further preparation' in the finishing sense. Both tanned and retanned crust sheepskins fall under this heading; the distinction becomes relevant when specifying the tannage system (chrome, vegetable, or combination) for end-use compatibility.