The best way to dispose of a hard copy of a customer design document is to shred it using a shredder. This is because shredding ensures that the document is destroyed and cannot be reconstructed or accessed by unauthorized persons. A customer design document may contain sensitive or confidential information that could cause harm or damage to the customer or the organization if disclosed. Therefore, it is important to protect the confidentiality and integrity of the document until it is securely disposed of. Throwing it in any dustbin, giving it to the office boy to reuse it for other purposes, or reusing it for writing are not secure ways of disposing of the document, as they could expose the document to unauthorized access, theft, loss or damage.
ISO/IEC 27001:2022 requires the organization to implement procedures for the secure disposal of media containing information (see clause A.8.3.2). References: CQI & IRCA Certified ISO/IEC 27001:2022 Lead Auditor Training Course, ISO/IEC 27001:2022 Information technology - Security techniques - Information security management systems - Requirements, What is Secure Disposal?