Aurora autoscaling and deletion

Hi, I am creating aurora cluster, with 2 instances of aws_rds_instnace and then configure autoscaling for the cluster aws_appautoscaling_policy. The problem is that on deletion the 2 instances get deleted but the autoscaling instances stay there (the policy is deleted) and prevent cluster from being deleted. What is the proper way to add the scaling to the cluster to ensure autoscaled instances are destroyed correctly?