def METHOD_NAME(self, tmo=60):
    """Remove testing files from system image"""
    tag_dir_list = [(t, d[1]) for t, d in six.iteritems(self.disks_info) if d[0] == "system"]
    if tag_dir_list:
        tag, root_dir = tag_dir_list[0]
        files = ["%s/%s" % (root_dir, f) for f in self.files_info[tag]]
        rm_cmd = "rm -f %s" % " ".join(files)
        # restart main vm for the original system image is offlined
        # and the mirror image is attached after block-mirror
        self.prepare_main_vm()
        session = self.main_vm.wait_for_login()
        try:
            session.cmd(rm_cmd, timeout=tmo)
        finally:
            session.close()