**Clean an installed Fedora OS:**

====== clean /var/cache ======

===== /var/cache/Packagekit =====
[[http://unix.stackexchange.com/questions/265755/fedora-23-can-i-safely-delete-files-in-var-cache-packagekit-metadata-updates|Source]]
<code> sudo pkcon refresh force -c -1 </code>
<code> rm -f /var/cache/PackageKit/metadata/updates/packages/*</code>
Disable the saving of the rpm's: \\ 
Edit ''/etc/PackageKit/PackageKit.conf'' and remove the # of ''KeepCache'' <code>
# Keep the packages after they have been downloaded
KeepCache=false </code>

===== dnf =====
<code>dnf clean all --enablerepo=\* </code>

====== clean /var/log/journal ======
[[http://unix.stackexchange.com/questions/130786/can-i-remove-files-in-var-log-journal-and-var-cache-abrt-di-usr|Source]]

You can delete everything inside of /var/log/journal/* but do not delete the directory itself. \\ 
  * You can also query ''journalctl'' to find out how much disk space it's consuming: <code>
$ journalctl --disk-usage
Journals take up 3.8G on disk.</code>
  * You can control the size of this directory using this parameter in your ''/etc/systemd/journald.conf'': \\ ''SystemMaxUse=50M''
  * You can force a log rotation: <code>
$ sudo systemctl kill --kill-who=main --signal=SIGUSR2 systemd-journald.service </code>
  * You might need to restart the logging service to force a log rotation, if the above signaling method does not do it. \\ You can restart the service like so: <code>
$ sudo systemctl restart systemd-journald.service </code>