Can I automatically purge every package I've ever uninstalled?

As an Ubuntu noob, I install and uninstall a lot of packages, to try them out. However, for months, I made the mistake of using apt-get remove instead of apt-get purge, which I didn't even realize exists.

Is there a way to cause apt-get to purge every package I've uninstalled? My system is full of leftover files I neither want or need from dozens of different packages.

A simpler alternative, using aptitude (not installed by default)

sudo aptitude purge '~c'

~c is an aptitude search pattern, it means 'Select packages that were removed but not purged'. (The single quotes are to prevent the possible expansion of ~c by the shell as the home directory of a user c.)

Note that purging will remove system configuration files, usually located in /etc, but personal configuration files, usually in some hidden directory in your home, are not removed (it is not always simple to know which they are).

https://help.ubuntu.com/community/AptGet/Howto says:

dpkg -l | grep '^rc' | awk '{print $2}' | xargs dpkg --purge

those two will clean your packages, but you should get in the habit of using this,

sudo apt-get remove --purge <package name>

that will purge the packages.

also check this out, this an utility called ubuntu-tweak, it has a feature that is called janitor, that lets you see the packages to clean, and even the configs. http://www.howtogeek.com/112974/how-to-customize-ubuntu-with-ubuntu-tweak/