To uninstall emacs24-common-non-dfsg just follow these instructions.
/debian/jessie/non-free///install/index.html GNU Emacs common non-DFSG items, including the core documentation Debian 8.0 non-free/editors 24.4+1-2
sudo apt-get remove emacs24-common-non-dfsg
Which will remove just the emacs24-common-non-dfsg package itself.
sudo apt-get remove --auto-remove emacs24-common-non-dfsg
This will remove the emacs24-common-non-dfsg package and any other dependant packages which are no longer needed.
If you also want to delete your local/config files for emacs24-common-non-dfsg then this will work.
sudo apt-get purge emacs24-common-non-dfsg
Or similarly, like this emacs24-common-non-dfsg
sudo apt-get purge --auto-remove emacs24-common-non-dfsg
|Description||GNU Emacs common non-DFSG items, including the core documentation|