After reading this thread, am i safe in guessing that you cannot list directories in a tar exclude file? In my backup-excludes file I have:

[note this backup file is used on a script that backs up mount share points on 8 pc's at //host.pc.ip.address/dock where /dock is C:\\Documents and Settings on the PC]

Code:
*.mp3
*.MP3
*.au
*.AU
*.aiff
*.AIFF
*.aif
*.AIF
*.rec
*.REC
LocalServer
NetworkService
All Users
My Music
Temporary Internet Files
Uncut Podcasts
Should I be dumping the files in the directories listed under *.REC into this backup-excludes file?

Since I have a script that runs tar on 8 different hosts, should I write the command
Code:
ls -R //hostip/dock/path/to/directory_to_be_skipped_name > backup-excludes
before my tar command in the script?

Since I'm running this backup script weekly/monthly on 8 different pcs, I can see the backup_excludes file getting extremely long. Is there a way to then delete what I just added after that tar command excecutes?