The metal threads of the historic period, made mainly from precious metals – gold and silver -, are considered as the first artificial fibers manufactured by humans: Delicate wires and sheet-bands, single or combined with other natural – animal or plant – fibers were widely applied in manufacturing and decorating valuable textiles. In this article the materials and techniques of manufacturing metal threads are described, and the various methods – mechanic, chemical, etc – of cleaning that have been used for the restoration of textiles are analyzed. At the same time, the technical and ethic limitations and the problems inherent in the various methods of cleaning, due to the simultaneous presence of heterogeneous materials (e.g. metals combined with plant or animal fibers and organic pigments), are detected and recorded. Finally, the especially important role of the pedantic preliminary examination and identification of all, if possible, the materials used is underlined. This procedure can help the restorer to make a factual decision as regards the kind and extension of the proper and safe interventions, necessary for the restoration of textiles of the historic period, which are interwoven or decorated with metal threads.