You can delete the contents of your build library. Be very careful when doing this, as build library files are not versioned.
The pbl.py client supports both single-file and recursive deletion. Try a command like this:
pbl.py delete -l http://$external_host/cubit_api/1 --project=myproject -t pub -r /foo/bar/baz/Release.zip -c "Deleting this file because it is no longer needed"
When deletion of a non-empty directory is requested, the --force option must also be specified. This is to help insure that you do not accidentally remove entire directory trees. In this example, we delete the entire subdirectory that contains the file we have just been working with, and we use the -c option to leave a comment in the audit log to explain why the deletion was performed.
pbl.py delete -l http://$external_host/cubit_api/1 --project=myproject -t pub -r /foo/bar -c "Deleting this subdirectory because the baz release has finished" --force
Finally, the --dry-run option can also be used with the delete option. If the --dry-run option is specified, no files will actually be deleted.