Metacat

Detritus accumulates in the 'temporary' directory. Output files generated by read requests may persist for the lifetime of the application server and will not be cleaned on abnormal termination. Copies of data files are left in the 'uploads' directory.

Temporaries should at least be cleaned on startup/config.
Better to remove them immediately after use or schedule a definite deletion
Why are these operations staged through temporaries at all?
Why does metacat implement its own temporary file management rather than use app-server provided facilities?