Classification of composite goods: which material decides?

Which material decides the classification of composite goods? In a recent judgment, the EU General Court gave the newest answer: decorative paper impregnated with melamine resin - declared as paper, duty-free - is classified as plastics at 6.5%, because the resin, not the paper, gives the product its essential character. The rules that produce such results regularly surprise. Why was a product of 72% plant fibres also classified as plastic? Which of the general rules do declarants - and, in one dispute, even supreme court judges - apply wrongly? How can a synthetic stone of one millimetre, invisible when the product is worn, decide the classification of a leather bracelet? Why did it not help the importer that the resin was not yet fully cured at import? And how did a classification opinion adopted forty years ago answer a question that still took two expert reports and three courts to settle? This article sets out the method on the newest case law and WCO practice: the five-step sequence, the removal test for essential character, the evidence file that wins these cases, and the checks - most of them free of charge - that would have answered these disputes before they began.