`In a Mac OS 10.4 managed client / networked home environment, burn folders, once created, cannot be removed by the user. The only way to remove them is to log into the server as root. Do a find (Command-F) for "fpbf," which is the file extension for burn folders. You can then select all and drag them to the trash from the find window.
[robg adds: I can't confirm this one, nor do I know anyone using such a setup. If you can confirm and/or deny, please post a comment and I'll modify the hint as necessary.]

