What does this do?
Cleanup: iCleaner can remove unnecessary files from your device. The cleanup process is made of the following steps:
Safari: it deletes cookies, browsing history and cache files to free up memory and preserve your privacy.
Applications: it deletes unnecessary AppStore apps caches, cookies, temporary files and snapshots. Furthermore, it detects popular applications for a more in-depth cleanup.
Known Apps: Atomic, Badoo, Dolphin, Downloads, Facebook, Facebook Messenger, Flipboard, Google, Google+, Google Maps, iCabMobile, iFile, Instagram, Mercury, Skyfire, Snapseed, SoundCloud, Soundhound, Sparrow, Tweetbot, Twitter, vShare, Wikipedia.
More apps are added with each subsequent release. User login data, useful cookies and other relevant files are left untouched. iCleaner only removes the unnecessary.
Log files: it deletes apps log files and crash reports from known locations. These files are generally irrelevant to the user and can be safely deleted.
Cache files: it scans and deletes system cache files and databases. Some of them are rebuilt upon respring. This helps removing obsolete cache data.
Temporary files: it deletes temporary files from your device. These files are meant to be removed automatically, but they often happen not to. iCleaner takes care of that.
Cydia: it cleans up Cydia caches and temporary files, Cydia applications unnecessary files, partially downloaded Cydia packages and repo files.
Cydia sources (disabled by default): it deletes Cydia sources files. As a result, Cydia will not list any package and the sources will have to be updated. This is disabled by default since it's only helpful if Cydia sources aren't updating correctly.
Unused dependencies (disabled by default): issues the "apt-get autoremove" command in order to remove packages installed as dependencies that are not needed anymore. Additionally, it removes preference files left by some uninstalled packages and removes unneeded entries from the "/var/lib/dpkg/status" file.
This is disabled by default since it should only be used by experienced users who want to automate the operation. Note that removed packages and preferences are not included in the "analyze" filesize count.
Filetype cleanup: iCleaner features a custom cleanup pass based on file extensions. By default, it looks for log and temp files all over the directory tree.
You might want to add more extensions (such as "bak" or "old"), but remember to use this with caution! Also, note that iCleaner will only accept alphanumeric characters via GUI (non-alphanumeric ones will be removed as you confirm), while it accepts any symbol via terminal (wildcards too).