Deleting old maildir messages, is what I'm doing OK?

[Chris Green]

This isn't specifically mutt but it's definitely to do with managing
mail and there's lots of knowledgeable people here.

I currently have the following two lines in my crontab to delete old
mails in my junk catching directories, is it OK/safe to do it like
this? 

    20 02 * * * find /home/chris/mail/Ju/*/cur -type f -mtime +7 -exec rm {} \;
    30 02 * * * find /home/chris/mail/Ju/*/new -type f -mtime +7 -exec rm {} \;

This isn't managed by Dovecot or anything so I have to have a DIY
solution.

-- 
Chris Green