Dos & Don’ts of Email Hygiene

When cleaning your lists, it’s important to realize there’s a right way and a wrong way with regards to email hygiene. Use our 5 quick tips to familiarize yourself on the right way to clean and validate and avoid the common mistakes people make:

1. DO Clean your list just prior to an email deployment. Take advantage of the up to date scans and validated emails right before you deploy a campaign in order to maximize deliverability.

DON’T Clean and wait. One of the most common errors that mailers make is cleaning their lists and sitting on that cleaned data for weeks or sometimes months before deployment. Data is dynamic, thus, emails will change over time. What’s clean today may not be clean tomorrow or a week from now. Average attrition rate on top level domains (Hotmail, Yahoo, Gmail, AOL, etc.) is 1-3% month over month. Therefore, It doesn’t make sense to invest in a cleaning that becomes obsolete after weeks of shelf time.

2. DO Clean your Openers and Clickers every 30 days. Mailing clean and verified data can yield a great return for opens and clicks. Segmenting your opener and clicker data is a common and successful practice for all mailers to target your most engaged users. However, you need to maintain the integrity of your ‘engagement’ data, as you will see that active doesn’t always mean clean.

DON’T assume that because something clicks or opens, it’s safe or clean. Active data is a great metric for deployment success, but not for cleanliness of your data. Some of the dirtiest data can come from active data. Cleaning your most engaged users consistently will prolong health of the list and mailing resources, as well as lead to continued success.  

3. DO validate and clean your data for both delivery-based and reputation based threats. Removing hard bounces and undeliverable emails is only half the battle. You also need to remove spam traps, dormant accounts, honey pots, monitoring seeds, click bots, high level complainers and potential litigators. Make sure you’re getting a robust solution that includes both ends. If that means using more than one solution to optimize the cleaning potential, so be it.

DON’T assume that since you validated the emails to delivery more successfully, that they are also safe to send to. Delivering an email is great, but delivering to a harmful email is not. A common mistake for an emailer is to verify data, but not clean it. The two are, by definition, very different. Just verifying data does well for eliminating hard bounces and other delivery based issues, but cleaning the data will also eliminate reputation based issues like spam traps, dormant accounts, bots, complainers, etc. This is the nefarious stuff that gets your IPs and domains poor reputation and thus a poor mailing footprint. Do your diligence on both service levels to ensure that you’re getting the most robust solution to include all aspects of email list hygiene and validation within your scans.

4. DO review your results and dissect the reports. It’s good to know what you’re getting back as a result of your cleanings. Things that are just black and white or “yes” and “no” don’t give enough information. Granularity is king. Make sure removals within your hygiene or cleaning give you the specific reasons as to why they were removed. Just lumping a suppression together and saying ‘BAD’ won’t help you understand or educate yourself on the whats and whys. Understand what’s being reported back from your solutions as that will help you gain insight into your list quality.

DON’T assume that scrubbing MORE out of your list is better. Over-scrubbing is a very common problem with some vendors. Many of them still use the ‘suppression’ method for scrubbing. They collect bad email addresses for various reasons through various 3rd party sources and build a large database of emails to then use as a benchmark to remove from your lists. This leaves no information as to why these are being removed, who removed them, how reliable are the sources, etc. This also leads to many false negatives, which in turn, leaves you with less data. It’s not the total amount of emails you remove that indicates a successful clean, it’s removing the ones that are truly a threat and leaving your list in good health and in good quantity. It’s about trimming the fat, not the meat. A good solution will give that quality, provide valuable information, and explain results to give you the transparency and confidence that what you paid for has true value.

5. DO educate yourself on the terminology for hygiene. Understanding your results is crucial to getting the most value from an email list hygiene solution. Knowing the difference between a soft or hard bounce can bring awareness to responses you may get from your ESP after a cleaning to determine if delivery issues are the fault of the list or the ESP. Knowing the differences between an anti-spam site trap and an ISP trap can help identify black list issues with an anti-spam network or service vs delivery based problems due to old converted accounts. Educating yourself on disposable email vs dormant email will help you in determining if your problems stem from sign up or over time from attrition. A good solution takes the time to explain and walk you through these so you’re aware of your lists strengths and weaknesses.

DON’T buy into the hype. Email list hygiene and validation should be very straight forward. Too often, vendors will sell you on where their information comes from or how they get their sources. Instead, they should be telling you what their service can and can’t do. If you’re being oversold, there’s a reason. Compensating for service level with fancy background stories or unrealistic sources won’t solve your issues. Technology always has a funny way of showing how good of a job it’s doing when you put the results to production.

These 5 quick Dos and Don’ts tips will ensure that your cleaning practices are up to date, working properly, and giving you the optimal solution you need to have a successful and prolonged mailing venture. For more helpful hints or cleaning tips – head over to or contact

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