public void Clean()
        {
            // get a list of existing packages at time of calling. It is vital that new packages not be created
            // while clean running, they will be cleaned up as they are not on this list
            IEnumerable <string> existingPackageIds = _indexReader.GetAllPackageIds();

            this.LockPasses = 0;
            this.Clean_Internal(_settings.RepositoryPath, existingPackageIds, false);
        }