1. Run VG=/dev/blah scripts/clean-schroots as root to make sure that
     the build chroot is not mounted, substituting the name of the
     volume group for blah.

  2. Look in /etc/schroot/chroot.d/ and delete the file
     corresponding to the chroot.

  3. Run lvchange -an blah/chrootname
     substituting the name of the volume group for blah and the chroot
     name for chroot.  Example: lvchange -an dink/gutsy-i386-sbuild

  4. Run lvremove blah/chrootname