Removing a group or site in Harvest / Grafana /Graphite



We are using NaBox for our implementation of Harvest / Grafana/ Graphite. It's really a wonderful tool and easy to use and implement. 


Quick question:


How do I remove old systems and groups from Harvest / Grafana / Graphite?


I see the data here via the shell:





Simply deleting the directories above though causes Grafana to stop serving pages. Is there another method?


Thank you,


Adam P