Board Thread:Support Requests - Getting Started/@comment-12711878-20140730182359/@comment-1330470-20140730183509

The reason that the prior history is maintained is to have a complete record of authorship, as is necessary for the Creative Commons licensing of Wikia. If you delete history just to clean up, and you remove the record of an individual's contributions that persist in later revisions, you are violating the license and may get in trouble.

However, it's possible to do in the case of vandalism that was completely and permanently removed. If someone added a nasty word to a page, and then another, more reputable user reverted the page to exactly the state it was before the nasty edit, then you can safely delete the revision, because their vandalistic contribution did not persist in any future revisions.

The procedure for doing so: Delete the entire page, then restore the page, but only restore the good revisions.