After install and uninstall some packages or softwares, your system will left some unusable libraries and configure files. You can easily to remove them by the following method :
sudo apt-get autoremove
sudo apt-get clean
sudo apt-get install deborphan gtkorphan
Now, from your “System” — “Management” — “Remove orphaned packages”, select “Options” and then click “Show uninstalled packages with orphaned configuration files”. If there is any, select them all and click “Confirm” to remove them.
Tidy your system up easily!