Relevant passage:
5-705. Methods of Destruction. Classified material may be destroyed by burning, shredding, pulping, melting, mutilation, chemical decomposition, or pulverizing (for example, hammer mills, choppers, and hybridized disintegration equipment). Pulpers, pulverizers, or shredders may be used only for the destruction of paper products. High wet strength paper, paper mylar, durable-medium paper substitute, or similar water repellent papers are not sufficiently destroyed by pulping; other methods such as disintegration, shredding, or burning shall be used to destroy these types of papers. Residue shall be inspected during each destruction to ensure that classified information cannot be reconstructed. Crosscut shredders currently in use capable of maintaining a shred size not exceeding 1/32 inch in width (with a 1/64 inch tolerance by 1/2 inch in length) may continue to be used. However, any crosscut shredders requiring replacement of the unit and/or rebuilding of the shredder blades assembly must be replaced by a crosscut shredder on the latest NSA Evaluated Products List of High Security Crosscut Shredders. The list may be obtained from the CSA. Classified material in microform; that is, microfilm, microfiche, or similar high data density material; may be destroyed by burning or chemical decomposition, or other methods as approved by the CSA.