BleachBit is a free open source disk cleanup utility for Ubuntu Linux, and other Linux distro which you can use to remove your temporary junk Ubuntu Linux system and internet files.
All you have to do is type in BleachBit in Ubuntu Software Center to install BleachBit with Ubuntu Software Center wizard.
When you are done installing. go to Applications > System Tools> BleachBit.
The root shortcut for BleachBit deletes junk files related to the root user and directories, and the regular BleachBit shortcut deletes junk files related to applications like Firefox, WineHQ, etc.
When I ran a BleachBit Root scan, it found 386.1 MB of Junk/Temporary files.
When I ran a BleachBit Regular scan, it found 438.6 MB Junk/Temporary files.
Using BleachBit also protects your privacy since it deletes your temporary internet files, tracking cookies, and your web browsers history.
You should be careful not to delet something you need. It is best to run a preview scan before you run the actual delete in BleachBit disk clean up.