Artifacts in CEE's Project Tracker cannot be directly deleted from a project; however, they can be moved to another project and when that project is deleted, the artifacts will also be deleted. You can create a project expressly for this purpose, move the artifacts you want to remove into the project, and then delete it.
You do not get back the artifact IDs when you move artifacts out of the project or when you delete the project containing the artifacts.
For audit purposes, some Project Owners choose to keep the target project where they moved the artifacts, so that anyone trying to view them will see a reason why they were 'deleted' from the original project.
The same artifact attributes must exist in the target project in order to move the artifact to that project, otherwise the move will fail. If the move is forced, the data in those fields will be lost.