The document discusses GMP guidelines for the rejection, reprocessing, reworking, recovery of materials and solvents, and returns of intermediates and APIs. It provides definitions and guidelines for each topic. Specifically, it states that rejected materials can be reprocessed or reworked if properly evaluated and tested to ensure equivalent quality. Recovered materials and solvents may also be reused if approved procedures are followed to ensure they meet standards. Returns must be identified, evaluated, and either reprocessed, reworked or destroyed depending on their condition.