The developers at cPanel removed the aging option in the latest version. However, you actually don’t need to have the email address setup in Mail > Add/Remove/Manage Accounts.
For example, let’s say you want any emails that goes to firstname.lastname@example.org to forward to email@example.com. You don’t have to set up firstname.lastname@example.org in Mail > Add/Remove/Manage Accounts.
Just go into cPanel > Mail > Forwarders > Add Forwarder.
In the first box you would enter ‘sales’ and then you would select the correct domain (if you have more than one domain set up). In the second box you enter email@example.com.
Now, when someone emails firstname.lastname@example.org, the email will be forwarded to email@example.com. This way, nothing will be sitting on the server taking up space and you won’t have to worry about cleaning up old emails.