You can delete any artifact except an outline. An outline is a required part of a database, so you must delete the database to delete the outline.
To delete an artifact, use a tool:
Tool
Topic
Location
Administration Services
Topics on deleting the specific artifact; for example, Deleting Rules Files
Oracle Essbase Administration Services Online Help
MaxL
drop object
Oracle Essbase Technical Reference
ESSCMD
DELETE command for the artifact to delete