Yes open Terminal from the Assessory menu and go
sudo nautilus
this will ask for you log in then open.
Click on the file system/grub/list.
Delete the lines you don't want. Leave those surrounded by #

I'm using Kubuntu, is it still Nautilus?

Well try it because I think it should be there for you.

Well -- apparently Kubuntu doesn't have a Nautilus around,
so I simply used the ah -- what is it? Konqueror, maybe? -- window,
right-clicked and selected "edit as root". I simply commented the
lines out -- they're still there, they just begin with a #. (Would a
/ or a REM do as well?

is it kernel lines you want to get rid of? if so you can uninstall
those with the package manager and it will remove the lines from grub