Removing Content or Invalidating Content
If you choose to remove content from the edge network, edge servers will re-retrieve the content from the origin server the next time they receive a request from one of the specified URLs.
If you choose to instead mark the content as invalidated, edge servers will revalidate the freshness of the content with an HTTP conditional GET (If-Modified-Since) request the next time they receive a request for one of the specified URLs. If the content has changed, the origin server will return a fresh copy of the content. If the content has not changed, the origin server will return an HTTP 304 Not Modified response, using less network bandwidth than if content were returned.