I moved my DE to XFCE! How does one safely remove old GNOME parts?

I did the same thing, got rid of Gnome's things and changed to XFCE. The only thing I can tell you is use trial an error. And I would also add that things don't really "break". As long as you have access to a command line and an internet connection you can always add the packages back. Or exchange them for something else.

For instance I got rid of nautilus and use XFCE's Thunar
Got rid of GEdit and use Mousepad
Got rid of gnome-terminal and use xfce4-terminal, etc.

Look into different applications and use what you like. It's the great thing about using GNU/Linux, the sky is the limit!

I hope this helps a bit. Hopefully someone can be of more assistance, because unfortunately I don't document my customizations (to my own frustration sometimes).

I am not sure, but I am inclined to think that a

sudo apt-get remove --purge gnome-*

should do the trick. However, I would feel better if someone could validate that.

I know if you will do a sudo apt-get remove --purge gnome-* -s it will show you what it will remove without actually doing it.

Probably the easiest way is to go the other way around. Install a bare bones system and then tack on xfce.

Put this in a terminal :
for app in /usr/share/applications/*.desktop ~/.local/share/applications/*.desktop; do app="${app##/*/}"; echo "${app::-8}"; done

It should display all the apps you got on your system.
I got that line somewhere on the web, I didn't put it together myself.
It seems it goes in those mentioned paths, taking all the apps in desktop, "do" something I don't get (maybe temporarily put them in a folder?), and then display them.

You should be able to identify those with the word "gnome" in it, like these :

gnome-background-panel
gnome-bluetooth-panel
gnome-color-panel
gnome-control-center
gnome-datetime-panel
gnome-display-panel
gnome-flashback-services
gnome-info-panel
gnome-keyboard-panel
gnome-mouse-panel
gnome-network-panel
gnome-online-accounts-panel
gnome-panel
gnome-power-panel
gnome-power-statistics
gnome-printers-panel
gnome-region-panel
gnome-screen-panel
gnome-sound-panel
gnome-sound-recorder
gnome-system-monitor
gnome-system-monitor-kde
gnome-terminal
gnome-universal-access-panel
gnome-user-accounts-panel
gnome-user-share-properties
gnome-wacom-panel
gnome-wm


The best way is to open synaptic and remove the gnome parts you decide to be useless "manually" (which is a pain in the neck - I agree with lembas here (the reinstallation can use netinstall, or Debootstrap if you want to learn it (I think you should......but I guess you don't really need to)).

Thanks guys, very useful info for me.

Usually I use xfce4 without remove everything of GNOME.

^ as lembas said. best way. cleanest and will give you a polished and stable system.
The alternative is removing parts manually from synaptic (easiest way) as David pointed out.

If you are going to try to install xfce from a clean base, keep in mind that you might have problems getting subtle things to work. For example if you first install xfce and then install lightdm you might find that you can't login. If you install lightdm without it's recommended packages, you will be able to login, but will be missing the lightdm theme, but also stuff like policykit (which allows you for example to mount an USB without entering a password) and other stuff also.

It's better to try it in a VM first.