If you’re sitting on a list (opt-in of course) that you just haven’t sent *any* emails to—ever—then you’d need to look at your timestamps to clean out old emails.

If you’ve been emailing on a fairly regular basis, then you are correct: MailChimp would be “cleaning” your list of bounces, unsubs, etc., automatically for you. And the more frequently you send, the more cleaning we’d have done.

However, even though MailChimp might be cleaning things regularly for you, you *still* might want to try segmenting your list based on exactly how “active” your subscribers are. You’ll find that the actives will respond better.

Here are some tutorials on how to do that:

http://www.mailchimp.com/blog/3-quick-email-list-segmentation-examples/

I assume that if the email address goes bad, it gets cleaned through the bounce process with MailChimp or they unsubscribe.

If we should clean it, how do we do that with MailChimp?

i have had this problem since the summer and its been very erratic, sometimes they go through and sometimes they don’t…i am letting MailChimp auto clean my emails lists so its not that i am using old emails, they are all people that indicated they want to receive info from my client.

You can at least lurk around and see what senders are asking about comcast (and other ISPs).