How do I clean a 7-year old list with 2.8 million emails?

DJ Waldow

This was a recent question posted on the forum of the Email Marketers Club* (EMC). Within minutes, the comments started flooding in. This was a no-brainer. A softball. My reply?

Simple answer. I’d recommend lopping off all email addresses that are over 1 year old. Don’t send to them – ever. I blogged about the reasons why a few months back: Email Address Shelf Life. Risk > Reward.

I was encouraged by other EMC members echoing and elaborating on my sentiments. The beauty of an active community is that they jump all over forum posts like this one. A sampling of some of the comments:

  • “The longer and older is your mailing list the bigger is your problem. if you start sending a lot of invalid emails to Hotmail or Yahoo! you will be blocked.”
  • “I would second the opinion of not sending anything over a year old. I would make sure you set the expectations with your client on the possible pitfalls of mailing data this old. I don’t recognize some emails I signed up for 6 months ago never mind 6 years ago.”
  • “The best list is never the largest, but rather the most receptive to your message.”
  • “Good luck sending that list without getting booted by your ESP.”
  • “Why would you use a service to clean a list that so obviously just needs truncating? DJ is right, as most of the time of course, you need to dump contacts.”
  • “Quite frankly your client needs to wake up. A 7 year old list with 2.8 Million contacts has just wasted them, at the very least, 6.5 years of time.”

The individual with the original question was not giving up easily. He wrote:

This [sic] people have a very well know website, very popular, and until 3 – 4 years ago they used to send a monthly newsletter to this list. Now they are planning to re-start the newsletter using our services. They say that the first couple of years they had opt in, and for the past 4 years or so, double-opt in.

I almost lost it. My reply…

Well known, popular, etc does not exempt them from having a bad list. Again, my recommendation is to chop off all emails that are >1 year old. Double opt-in or not…get rid of them. Too much changes in a year. Email addresses go dormant (leading to honeypot addresses). Dedicated IP or not, if you send to a 7 year old list, your IP will get blocked. Not good for a well-known company, right?

It seems like this topic has been a hot one this week. Our friend Ben Chestnut of MailChimp blogged “Real stats: How sending to old lists will kill your deliverability.” One of the sharpest minds in the industry, Stephanie Miller of Return Path, fired back a cautionary reply in her post, “The Risks (and Sometimes Rewards) of Not Following Best Practices.”

The moral of the story is this: Sending to an old list is very risky and most often far outweighs the benefits. It is no longer good enough to just “do” email marketing. Smart, strategic, best practice email marketing always wins.

DJ Waldow
Director of Best Practices & Deliverability at Bronto

*The Email Marketers Club is social networking site with over 1800 members founded in May 2007 by Tamara Gielen of BeRelevant. It provides a platform for email marketers across the globe to network and share information and experiences with each other.

  • We have done some research at Infusionsoft on our customers complaint rates and found that complaint rates for their customers over one year old are almost double. This doubling of complaint rates will for almost all business result in blocks from major ESPs. If you are discouraged by the idea of not being able to send to older leads you will be more discouraged when you can’t send to any of your leads or current customers due to email blocks.

  • DJ,

    What saddens me in all of this is that companies in these lean economic times will try anything to do produce results. Doesn’t make sense I know…but this is what companies are resorting too.


  • DJ Waldow

    @Ryan: Well said! Now, we need to continue to spread that message…

    @Andrew: True, but the “good” news is that the negative results (blocks) may lead some to think twice. Once your IP has been blacklisted, many learn their lesson and don’t want it to happen ever again. Many. But not all.


  • RT

    Where’s that simple test to clean up a messy list in no time? How does one determine which addresses are over a year old? We’re newbies who use an antiquated in-house system and will switch to a professional ESP this month. Thanks.

  • RT

    Thanks, DJ. Then I wonder what the Training Marketer was saying above when he wrote “Read the post to learn how to clean up a messy email list in no time.” In addition to the wisdom you’ve already provided, can you show me that post? Thank you very much.

  • DJ Waldow

    @RT: I only wish it were that easy. I think that is one of the biggest mistakes that marketers make when it comes to email marketing – they look for the “simple” way. The easiest way to clean up a messy list is to not send to it. However, I realize that is not always possible (i.e., pressure from boss, unable to segment out old emails, etc.). If you *must* send to an older list I would recommend sending in very small batches (5-10k at a time) with a clear, succinct message. Then, actively track the results looking for hard bounces, complaints, unsubscribes, etc. Tweak the batch size and message accordingly. Also, you may want to consider running a re-optin campaign. Hope this is helpful. Feel free to give me a ring to talk in person.


  • DJ Waldow

    @RT: The post from “Training Marketer” is here – I am not sure what s/he was referring to about advice on how to “clean up a messy email list in no time.” That is not really what this post (above) is all about. Would be happy to talk more. Give me a ring: 919.226.9363 x110.