How do I remove queues for Operations that have been deleted?

Hi,

My [Ensemble] > [Queues] page shows message queues for Operations that were deleted months ago.

When I deleted the Operations I thought Ens.Util.Tasks.Purge would cause the (empty) queues to disappear from the Queues page.

Is there a way to remove queues that no longer refer to an operation?

Kind regards,

Stephen