Summary
The general consensus among experts and marketers is that cleaning your email list before migrating to a new ESP is beneficial for several reasons, including maintaining a good sender reputation, improving deliverability, and increasing engagement. List cleaning involves removing hard bounces, unsubscribes, inactive users, and invalid email addresses. However, some experts question the necessity of cleaning lists that are Confirmed Opt-In (COI) and regularly bounce-managed, while others caution that list cleaning services may inadvertently flag valid addresses as bad. Some responders recommend a warm-up of the IP address with engaged users and automated systems for bounces and unsubscribes.
Key findings
- Improved Deliverability: Cleaning email lists helps improve deliverability by reducing bounce rates, spam complaints, and ensuring emails reach engaged subscribers.
- Enhanced Sender Reputation: A clean email list contributes to a positive sender reputation, leading to better inbox placement and email marketing success.
- Cost Reduction: Maintaining a clean list ensures that you're only sending to engaged subscribers, reducing costs associated with inactive contacts.
- Engagement Boost: Cleaning ensures your email campaigns reach active subscribers, boosting engagement and ROI.
- Importance of Opt-In: Confirmed Opt-In (COI) lists that are actively managed for bounces may not require extensive cleaning.
- Data Quality Matters: Maintaining high data quality through regular contact list maintenance improves deliverability and marketing alignment.
- Gradual IP Warm-Up: Warming up new IP addresses is crucial, and should be done with engaged users.
Key considerations
- Re-engagement Campaigns: Before cleaning the list, consider running a re-engagement campaign to win back inactive subscribers.
- Sampling First: If you choose to use a list cleaning service, start with a small sample to assess the impact and accuracy.
- Automate Systems: Implement automated systems to handle bounces, complaints, and unsubscriptions.
- Validation: The cost of validation is less than the cost of poor deliverability.
- Risk of Removing Good Addresses: Be aware that list cleaning services can make mistakes and remove valid email addresses.
What email marketers say
10 marketer opinions
The consensus among email marketers is that cleaning your email list before migrating to a new ESP is highly beneficial. It helps maintain a good sender reputation, improves deliverability by reducing bounce rates and spam complaints, and ensures that you're only sending to engaged subscribers. Running a re-engagement campaign before cleaning can help retain potentially valuable subscribers.
Key opinions
- Improved Deliverability: Cleaning your list reduces bounce rates and spam complaints, leading to better deliverability.
- Enhanced Sender Reputation: Maintaining a clean list helps preserve a positive sender reputation, which is crucial for email marketing success.
- Cost Efficiency: Sending emails only to engaged subscribers reduces costs associated with inactive contacts.
- Engagement Boost: Focusing on active subscribers improves overall email engagement rates and ROI.
- List Decay: Email lists decay due to unsubscribes, changing demographics, and inactive addresses; cleaning helps combat this.
Key considerations
- Re-engagement Campaigns: Before removing inactive subscribers, consider running a re-engagement campaign to win them back.
- List Cleaning Services: Using a list cleaning service can automate the process of identifying and removing invalid addresses.
- Email Verification Tools: Email verification tools, like Kickbox, can help identify and remove invalid or risky addresses from your list.
- Active vs. Inactive: Determining the right timeframe for subscriber inactivity will depend on factors such as your industry and frequency that you send emails.
Marketer view
Email marketer from OptinMonster shares that regularly cleaning your email list removes inactive subscribers, reduces hard bounces, and minimizes spam complaints. This increases your sender reputation and improves deliverability rates.
16 May 2025 - OptinMonster
Marketer view
Email marketer from G2 shares that using a list cleaning service can help identify and remove invalid or inactive email addresses. This improves your sender reputation and ensures that your emails reach engaged subscribers.
17 Feb 2025 - G2
What the experts say
4 expert opinions
Experts offer differing perspectives on cleaning an email list when migrating to a new ESP. One viewpoint questions the necessity of cleaning a list that is Confirmed Opt-In (COI) and regularly bounce-managed, while another suggests that legitimate list cleaning services may inadvertently flag good addresses, potentially reducing list quality. Conversely, other experts emphasize the importance of regular list cleaning to maintain sender reputation and improve deliverability, noting that the costs of poor-quality email addresses outweigh the costs of validation.
Key opinions
- COI & Bounce Management: For lists that are Confirmed Opt-In and actively bounce-managed, the need for extensive cleaning is questioned.
- Potential for False Positives: List cleaning services may incorrectly identify valid addresses as 'bad,' potentially harming list quality.
- Sender Reputation: Regular list cleaning (removing hard bounces, unsubscribes, and inactives) is essential for maintaining a positive sender reputation.
- Cost-Benefit Analysis: The costs associated with maintaining poor quality email addresses (deliverability issues, reputation damage) are higher than the costs of email validation.
Key considerations
- Sampling: If list cleaning is desired, start with a small sample to assess the impact and accuracy of the cleaning service.
- Automated Systems: Implement systems to automatically handle bounces, complaints, and unsubscriptions to maintain list hygiene.
- Validation Importance: Acknowledge the importance of email validation strategies in order to reduce deliverability issues.
Expert view
Expert from Email Geeks shares that a legitimate list cleaning service might flag addresses as 'bad', potentially causing concern and reducing list quality. He suggests it's a tradeoff between a bad business decision and good vibes for the customer, noting that it's not harmful, but the customer should start with a small sample.
2 May 2023 - Email Geeks
Expert view
Expert from Spam Resource explains that you should regularly clean your email list, including removing hard bounces, unsubscribes, and inactive users, to maintain a good sender reputation and improve deliverability. You should also consider setting up a system that handles bounces, complaints and unsubscriptions automatically.
13 Sep 2022 - Spam Resource
What the documentation says
4 technical articles
Technical documentation from various platforms emphasizes the importance of list cleaning and gradual IP warm-up when migrating to a new ESP. Maintaining high data quality by removing outdated, duplicated, or unusable contacts improves deliverability, protects sender reputation, and ensures messages reach the inbox. Starting with engaged subscribers helps build a positive sending reputation with mailbox providers.
Key findings
- Gradual IP Warm-up: Warming up the IP address gradually with engaged subscribers is crucial for building a positive sender reputation.
- List Cleaning: Removing inactive users, hard bounces, and providing clear unsubscribe options improves deliverability.
- Data Quality: Maintaining high data quality by removing outdated and unusable contacts is vital for marketing effectiveness.
- Sender Reputation Protection: Removing inactive recipients protects sender reputation and keeps bounce and complaint rates low.
Key considerations
- Engaged Subscribers First: Prioritize sending to engaged subscribers initially to establish a good sending reputation.
- Remove Inactive Users: Regularly remove inactive users to reduce bounce rates and improve deliverability.
- Unsubscribe Options: Provide clear and easy-to-use unsubscribe options to maintain list hygiene and comply with regulations.
- Monitoring: Carefully monitor the initial campaigns after switching ESPs to ensure there are no deliverability issues.
Technical article
Documentation from SparkPost explains that when migrating to a new ESP, it's crucial to warm up your IP address gradually. Start with your most engaged subscribers to build a positive sending reputation with mailbox providers.
27 Feb 2023 - SparkPost Documentation
Technical article
Documentation from Microsoft responds to question about keeping marketing contact lists current and healthy, it is vital to maintain high data quality. Detecting and removing outdated, duplicated, or otherwise unusable contacts will improve deliverability, reporting, and sales and marketing alignment.
25 Feb 2023 - Microsoft Dynamics 365 Documentation
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