WCO Explanatory Notes reproduced for reference. © World Customs Organization. Verify against official WCO publication.
50.06 - Silk yarn and yarn spun from silk waste, put up for retail sale; silk-worm gut. (A) Silk yarn and yarn spun from silk waste. This grou covers the yarns of headings 50.04 and 50.05 ut up for retail sale, i.e., in the (3) of the General Explanatory forms and?' subject to the conditions described in Part (I) Note to Section XI. (BY (B) Silk-worm gut. Silk-worm gut is obtained by extracting and stretching the silk glands of silk-worms killed by immersion in diluted acetic acid at the stage when the are ready to spin their cocoons. Silk-worm gut is less flexible and glossier than horse air, and rarely exceeds 50 cm in length. K The heading does not cover : (a) Sterile silk-worm gut (heading 30.06). (b) Imitation catgut of silk, of heading 56.04. (c) Silk-worm gut fitted with hooks or made up into fishing lines (heading 95.07).
Silk GENERAL The General Explanatory Note to Section XI should be taken into account in reading the Explanatory Notes to this Chapter. P For the urposes of this Cha ter the term " silk covers not only the fibrous matter secreted by the Bom%yx mori mulberry eeding silk-worm), but also the products of the secretion of similar insects e.g., Bom yx textor known as wild silk. Among the wild varieties, so named because the pro ucmg worm has on y very rarely been domesticated, the most important is tussah silk obta~nedfiom a silk-wonn that feeds on oak. Spider silk and marine or byssus silk (the filaments by which certain shellfish of the Pinna family cling to rocks) are also classified in this Chapter. Generally speaking, this at its vmous stages of silk-worm gut. " ter covers silk, including mixed textile materials classified as silk, from the raw material to the woven fabric. It also includes