New to Zimbra but loving it.

Was lurking around the forum but could not find anything that exactly fits this.
Basically this is the setup:
1 user account with several aliases emails
several folders inside inbox
rules that move aliases email to respective folder

these aliases are emails from facebook, or twitter, or shaddy websites registrations.... nothing major to keep but with high volume and taking space.

Would like to automatically delete these messages not by date "per si" from this date to that date but if older than.
so rules could be setup to delete messages inside a folder older than 2 or 3 or 10 days. different folders, different days.... but no dates, if older than.

Thanks