Where can I maintain (delete unused) analytic distribution instances

Where can I maintain (delete in particular) analytic distribution instances?

For example, on a Purchase Order Line, I can click the search button and create a new "Analytic Distribution" instance. Once it is created, I can also maintain it directly using the "Open this resource" button. However, I have not found any way to delete "Analytic Distribution" entries that were created, but never used, and thus represent unnecessary clutter.

Also, since open resource permits the modification of existing "Analytic Distribution" instance, I would have expected there to be a place to manage them, somewhere in the menu, maybe under Purchase Order or Configuration.

Kind regards,
Réal Carbonneau