Are the people that use the "excluded" computers all in a group together? If not, it might be a bit easier moving forward. What I've done in the past is add groups, for most if not all of your custom exclusions. It made it a lot easier for me to keep track of them. Not really sure where exactly you are having problems though, can you be more specific as to:
1) OS running AD you are using.
2) Steps you've tried
3) Specific problems stemming from those steps that you are experiencing.