I started on regenerating Keys from the API Management Server and worked. Tried Deleting it also but not quite the result I was expecting.
I was expecting that the App Key/Secret Pair would be removed from the DB but it seems it was only removed from the UI perspective. It is still accumulating in the backend everytime you ask for a regeneration and deleting it through REST Calls. Docs used for regenerating and deleting:
Regenerate: http://docs.apigee.com/management/apis/post/organizations/%7Borg_name%7D/developers/%7Bdeveloper_ema...
Is there anyway to completely delete it from the backend too ?