Removal of user files upon deletion of the domain/user itself

The following files owned by virtual server users are not deleted when a domain (and also users under it) are deleted:

/var/spool/mail/{user} /var/log/virtualmin/{prefix}_*

This is not a big issue except that it counts against the quota of newly created user which gets assigned the same UID by Linux (reuse of UID). For example, I recently deleted a domain and then someone else managing the server created a new email user. The newly created email user immediately ran out of quota with several GBs of space usage - resulting from the leftover files owned by previosly deleted domain.