Deleting old mail messages


I’m running 2 openSUSE 11 servers.

One collects mail from the Internet using Exim and routes it to /var/mail/user

Second one collects it by POP3 and moves it to an maildir for IMAP access.

I’m currently flushing each message when collecting it by fetchmail.

If I was to collect it using a client like Thunderbird, I can set it to only delete messages that are a few days old.

Instead of flushing /var/mail/user everytime I collect mail, rather I want to keep mail that is 5 days old or younger.

Is there anyway of doing this with fetchmail?

If not fetchmail can I run a cron job on the server that deletes messages that are over 3 days old?

I can’t find an answer for this anywhere.

With fetchmail it seems to be keep all messages or flush each one each time it is downloaded.