1. Creating custom boards. For example, a circuit board from an old router can be cut into small pieces and made into boards for amateur electronic projects. 2. Assemble components for reuse. Remove components from boards, such as those from an old video game console, to use in future circuits. 3. Learning kits. An old computer motherboard can become a soldering practice pad or a demonstration model in computer science classes. 4. Metal recovery and sales. Valuable metals can be recovered from circuit boards, such as gold from connectors or silver from other components. 5. Custom fabrication of enclosures for electronic devices. An old circuit board can become the housing for a new device. 6. Collecting old electronics for a constant flow of materials for new projects. 7. Powering a robotics kit. Think of a small robot assembled from the circuits of an old printer. 8. Swap components, parts, and ideas with electronics hobbyists.
When reusing old circuit boards, safety is paramount. Make sure the electrical characteristics of your PCB components match the requirements of the new equipment. Use components outside the intended voltage and current range.