The reason for this post is hilarious. In my life time I installed and over installed Ubuntu for period of times, but every time I had to ask my buddy or Google about removing annoying old Ubuntu core versions from Grub configs and from /boot directory. Well, now I will describe those two simple steps for those who have same problem as I did.
First Step: Remove old core files
Actually the order of those steps doesn't change anything, but logicaly I see it like this.
NB! I have to confess I didn't remove those files I just moved them to another place where I have more free space, but it's for you to deside what to do with them.
/bootdirectory. There you will see all those core files.
Next I just moved old versions to other directory. Last time I had those versions: 2.6.32-21, 2.6.32-22, 2.6.32-23, 2.6.32-24. My current and I think newest version is 2.6.32-24. For safety purposes I leave to last versions: *23, *24.
If you wish to store those old versions create some folder. I would recommend
If you chose step above, then do the following (in my case it was):
sudo mv /boot/*2.6.32-21* /home/$USER/dir/
If you want to delete those files, then do following:
sudo rm -f /boot/*2.6.32-21*
Second Step: Edit grub.cfg (or menu.lst)
Since I have grub.cfg I will describe how to edit it. Open
gksudo gedit /boot/grub/grub.cfg.
Between this line
### BEGIN /etc/grub.d/10_linux ###
### END /etc/grub.d/10_linux ###
you will find all those versions you see in "Grub Loader".
Find the versions you deleted or moved and delete those lines or comment them
As you could see those steps where easy as "a b c". Still if you have any questions ask them in comments or @netjunky.