Heading 150600 is a residual category covering animal fats and oils not specifically provided for elsewhere in Chapter 15. In practice, this can include fats from horses, rabbits, insects, or other species not enumerated in headings 1501–1505, as well as mixed-species rendered fats that do not fit a more specific description. Importers should work through the Chapter 15 classification hierarchy systematically before defaulting to this heading.

Admissibility depends on the source species and intended use. Fats from food-animal species intended for human consumption may require USDA FSIS oversight, while fats from non-food animals or for industrial use follow different pathways. USDA APHIS may also have jurisdiction over certain raw animal-origin materials. Because the heading covers a wide range of products, importers should confirm the applicable regulatory pathway with a licensed customs broker or the relevant agency before shipment.