[CentOS] CentOS 5 Xen Files Left in /var/lib/xen ..

I have a machine with four guests on it, and it seems to create and
leave lots of files with names like vmlinuz.LqKA3h and initrd.kolvQu in
directory /var/lib/xen. The remain there even when all guests are
gracefully shut down .. and additional ones get created when they are
next started.

The end result, of course, is that the root file system fills up. So ..
how can I prevent this from happening?

I've got SELinux disabled and I have Guest files in /XenGuests. I've
also set XENDOMAINS_SAVE="" in /etc/sysconfig/xendomains

Any ideas?
-- 
 Graham Jenkins +61 3 9925 4909 
 Victorian Partnership for Advanced Computing http://www.vpac.org/
 PO Box 201, Carlton South, Vic. 3053, Australia