Thank for your very helpful answers @PurpleShirt and @dvnkln. Both solve my problem, but unfortunately I can only set one post as solution 
. We are already successfully deleting obsolete test tickets, using a combined approach 
Thank for your very helpful answers @PurpleShirt and @dvnkln. Both solve my problem, but unfortunately I can only set one post as solution . We are already successfully deleting obsolete test tickets, using a combined approach