Bleachbit is a piece of software that is able to clean up the sum of all those tiny files that you never will be able to remove manually.
Even if you use a great program like ncdu there are lots of tiny auto-saved files from various programs.
And there are always the LOS (flash cookies) that are placed in ~/.macromedia/Flash_Player/#SharedObjects/ regardless of if you have chosen to block cookies or not. You will find a directory there with a random number and the content of it are the flash cookies.
You can turn these off as described here, but then once in a while you need that functionality they may offer (if you remove them after finally having made level xxx of angrybirds you would be back to level one
).The flash-cookies can also be nasty and track whatever....
So this is where bleachbit comes in and lets you make the occasional "house cleaning". It takes care of browser cache tmp and lots of other stuff that just adds up. Flash cookies will be removed too. You are in control and can pick what you want to clear.
I cleared 445 MB just by cleaning the Chromium bit.
