The process consists of checking out engineering part revisions. If an engineering part revision is not usable, it will be set to obsolete and then deleted. A usable part revision is defined as a part revision that will be used in the future. If it never will be used again, it should be deleted.
To check if a part is usable, it is necessary to check the spare part lists and the alternative part lists and then perform an evaluation about the usefulness of this engineering part revision in the future. Use Spare Parts and Part/Engineering/Alternative Parts to view all spare parts and alternative parts.