Starch-based (amylaceous) finishing agents fall specifically under 380910 regardless of the end-use industry. Synthetic or non-amylaceous finishing agents for the textile industry are classified under 380991. The composition of the carrier or binder — not the end-use alone — determines which subheading applies.

In principle, classification follows the preparation's primary intended use as declared and documented. A preparation marketed and formulated specifically for leather tanning goes under 380993, while a chemically similar product sold for textile use goes under 380991. Dual-use products should be classified based on the principal use supported by technical documentation and commercial invoices.