In How to Not Suck at Email Campaigns I completely left out a HUGE part of not sucking; scrubbing your email list.

Scrubbing an email list before sending it out is something that rarely gets done but is actually pretty crucial.

See, email providers, the organizations that provide email like yahoo, gmail and hotmail, and some spam filters, actually look at the email addresses you send to and flag those they deem to be either role accounts or spam traps and they use that to determine part of your spam score. If your spam score is too high; you’re a spammer.

This assumes you have an honest list to begin with. If you’re buying lists of email addresses from people and sending emails to them you’re a spammer and nothing here is going to help you. Oh yeah, everyone else knows you’re a spammer too.

Fuck you.

Anyway, I first learned of the importance of scrubbing a list while preparing one of my clients email databases for a blast (they hired StreetWise to send email on their behalf). During the import process into the mailing solution we were using our account was put in lock down which essentially stopped the entire project dead in it’s tracks. After contacting the mailing solution I got the below response:

I do want to be clear that the list both contains spamtraps, role accounts (such as admin@) and other addresses with aspects that indicate that some part of the list may not be completely opt-in. Spamtrap addresses are those addresses that have generally been retired or are known by the domains postmaster to be inactive and as a result unlikely to be signing up for new mailing lists. These addresses may also be ones planted on a website specifically for email harvesting purposes. Sending to them indicates a lack of an opt-in process, the ideal option being a double opt-in confirmation method where members must both submit their email address and respond to a follow-up email before receiving regular mailings from the list.

Mail sent to spam traps, as with non opt-in mail in general, may result in a loss of deliverability for a sender. This may include domain blocks (refusal of the senders mail by a domain) or blacklisting by spam prevention agenies and further hurts the reputation of the sender.

Combined with negative feedback from the recipients (sent either to the sender, its ESP, or the users postmaster), not honoring opt-out requests, sending to a large amount of non-existent members, spamtrap addresses call into question the entire lists credibility.

So just what do you need to scrub for? Well, duplicates, MX records for the domain and syntax issues obviously but, more importantly, specific keywords in emails.

To start you want to get rid of any email address containing the keywords below (* is wildcard):

junk*
admin@*
root@*
postmaster@*
blackhole*
confirm@*
fuck*
donotreply*
help@*
nobody@*
*@poop.com
support@*
sysadmin@*
*spam*
dev@*
devnull@*

That’s not a complete list of course; just the ones I’ve personally discovered to date. I plan on compiling a database of them once I get more and so should anyone who’s serious about not sucking at bulk email blasts.

There’s also spam trap email addresses. These are email addresses people sign up for that allow them to sign up for accounts and other services without actually giving their real email address.

They are insanely popular (and pretty annoying too).

So far I’ve only had to deal with a few though. You want to remove any email address from the below domain:

*@spamgourmet.com
*@sneakemail.com
*@mailinator.com
*@trashymail.com
*@mailexpire.com
*@temporaryinbox.com
*@spambox.us
*@spamhole.com
*@pookmail.com
*@spamfree24.*
*@kasmail.com

This is especially important on lists you’re sending on behalf of your clients. I have yet to have a client freely admit to having email addresses that haven’t been opted into properly; they always swear that their list is clean. I’ve seen HUGE corporations, we’re talking hundreds of millions of dollar companies, hand over lists that decreased over 20% once it’s scrubbed.

Cool thing is, though, that the client usually has no idea. Usually, someone told them they have a list of email addresses somewhere and, odd as this may sound, they’re actually thrilled to be told their list isn’t “good”. Makes you look like you know your shit 😊