How to manage, maintain and clean bounced
or undelivered emails from your database?

The most important thing to remember is that undeliverable emails does not necessarily means that they are invalid, because emails can be bounced for various reasons. It is recommended to delete email addresses after they are bounced or undeliverable between 4 to 6 recurrences.

Many ISP's mail servers are known to block or barred a sender email domain because they have repeatedly sent emails to non-existing account holders within their domain.

If you are broadcasting
emails via your ISP mail server?

The first step is to understand the mechanics of how and why emails got bounced or undeliverable in the first place.

When emails are sent from your MailsBroadcast program to your ISPs mail server--your ISPs mail server will accept all of them--at this stage your connection could be terminated, --and kept them in queue for delivery, sitting there for a few seconds or hours.

Most local legislation requires ISPs service operator to grant security service access to users correspondence before they are delivered to the recipient ISPs mail server--which may decline to accept them and your ISPs mail server may attempt multiple deliver before bouncing it back to you as bounced or undeliverable--within seconds, hours or days later.

Many ISP mail servers also reduce the number of concurrent connection--meaning that even thought your ISPs mail server have accepted all your emails--they may not be delivered or accepted by the intended recipient ISPs mail server. See: Server-time-out disconnected

Many ISP's mail servers are known to block or barred a sender email domain because they have repeatedly sent emails to non-existing account holders within their domain.

Because spammers are known to use software that generate random email addresses for spamming and don't bother to remove bounced or undelivered mails, hence, ISPs assumed that the sender is trying to spam.

If you are broadcasting emails using
your own computer mail server program?

Emails will first be sent from MailsBroadcast to your mail server program for delivery and if you are off-line (not connected to the Internet) your mail server will cache or store them in queue until the next delivery scheduled.
Next...

Your mail server sent-out emails--one by one--single thread or dozens at a time using multi-threads program--directly to the email recipient ISP mail server. Any undeliverable email will remain in your mail server cache for repeated delivery--depending on your settings.

All emails being sent-out from your own mail server will still be subjected to the same SMTP protocol conditions for acceptance or rejection by the recipient ISP mail server.
See: Server-time-out disconnected and identifying (soft or hard) Permanent failures SMTP Return Error Codes

Once, mails are accepted by the recipients ISPs mail server (unless the sender email domain have been blocked and mails are delete without notification) it is considered delivered – it means that if you are sending mails from your own mail server are either undeliverable or delivered.

Summary
Broadcasting emails through your ISP mail server
Bounced or undeliverable emails will be slower to be returned and you will most likely be restricted by time or quantity of emails allowed to be sent to both your recipients and ISPs' mail server.

Broadcasting emails via your own mail server
Bounced or undeliverable emails data will be available at your own mail server and you are not restricted in any way by time or quantity of emails sent.

Undeliverable email addresses from recommended mail server program, can be automatically transferred to MailsBroadcast bounced folder for "Global" removal from the entire database or clean each individual email list folder.

Which ever method being used to broadcast emails
They are subject to the basic core process of the five SMTP email transaction commands protocol for acceptance or rejection of emails by the recipient ISP mail server. And that, bounced or undeliverable emails does not necessarily means that the recipients are invalid.
See rfc2821 for the basic specification of SMTP

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Now that you understand why emails are bounced or undeliverable. After broadcasting, you will notice that your email list contains many returned undeliverable or bounced emails. It is not unusual to receive quite a bit of returned mail, even an up-to date list looses as much as 25% of their email addresses within a year and it is something that you have to deal with regularly by removing them from your list database.

The difficult part is that many ISPs return the undelivered email days later, together with the original message as an attachment and you have to open the attachment, to see the returned email address. And un-subscribers usually input all kinds of header message without following instructions.

Automated filtering and removal of returned or bounced emails is difficult because they originate from different worldwide International ISPs mail server and comes in many flavors that are not easily predictable. There not many short-cut to a tedious process of removing bounced mails, except...

Why do you need a few MAIL FROM email addresses?
It is recommended to have an unsubscribe address and a few MAIL FROM email address for broadcasting, because undeliverable mails are automatically returned (bounced) to the MAIL FROM address.

By using different MAIL FROM address for broadcasting different emails message--you will know which bounced or undelivered emails are for which newsletters sent.

Note: The REPLY TO email address is when recipients click reply to your email message; to unsubscribe or to send you a feed-back note--their email client (Eudora or Outlook Express) will automatically send it to your REPLY TO email address. This way it is easier to manage all your unsubscribed (REPLY TO) for removal from your email list and bounced (MAIL FROM)

MailsBroadcast cannot receive email, therefore, to delete returned mails or un-subscribers, you must an email client like: Outlook Express, Eudora, Netscape Communicator--to collect them and export the collected emails to a text file and then use the (Import Export) options at MailsBroadcast System Manager to import the returned email for removal by using the option at Email List Manager: Clean a list from another.

Undeliverable email addresses from recommended mail server program, can be automatically transferred to MailsBroadcast bounced folder for "Global" removal from the entire database or clean each individual email list folder.

The most important thing to remember is that undeliverable emails does not necessarily means that they are invalid and it is recommended to delete the email address after 4 to 6 undeliverable or bounce.

See: Customers confirmed that their emails are valid but some still get bounced?

Notes
It is also recommended to own a few different email domain address for broadcasting your newsletters etc., because; due to various unforeseeable circumstances your Internet access account and/or email may be temporary suspended and you need to be on-line as soon as possible--because your ISP may takes longer to respond than expected.

See: Email Rage

See: ISP suspend an Internet account based on erroneous or false spam complain