This question already has an answer here:
I have a list of packages on my system, that were installed and removed again, but not purged, i.e. there are still a lot of conffiles etc. laying around.
The output of
dpkg --get-selections | grep deinstall lists about 85 different packages which I don't need and want to be purged entirely.
So my short question, which I decided to finally ask after experimenting around has lead to this problem, is:
How do I completely purge previously installed packages that are already removed?
Reinstalling and then purging is not an option, of course.