There is no easy way.  Typically if deleting one by one is impractical, we'd do a full table dump to Excel, then re-init (delete all rows) and import the cleaned up spreadsheet.

The alias is part of the key so each alias is unique and unrelated to others. Do as Kevin suggest. It is how we do it to clean up.

Thanks Kevin.  How do you re-init?  Or do I need by reseller?

There is a utility in Library Master for that.  Be super careful... it is a powerful utility that can wipe out all your data if you choose the wrong table(s).  There is no "undo" so take backups!