BleachBit

BleachBit quickly frees disk space and tirelessly guards your privacy. Free cache, delete cookies, clear Internet history, shred temporary files, delete logs, and discard junk you didn't know was there.

https://launchpad.net/ubuntu/+source/bleachbit
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install:
Applications > Accessories > Terminal or Ctrl+Alt+T :

$ sudo apt-get install bleachbit

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