How to Clean Your Email List Before Sending a Campaign
· 6 min
Why list hygiene matters
Every email you send to an invalid address damages your sender reputation. Internet Service Providers (ISPs) like Gmail and Outlook track your bounce rate, and once it exceeds 2-3%, your future emails start landing in spam — even for valid recipients. Regular list cleaning is not optional; it is the foundation of email marketing.
Step 1: Export your list as CSV
Most email marketing platforms (Mailchimp, Brevo, ActiveCampaign) let you export your subscriber list as a CSV file. Make sure the file has an "email" column header. If your file is in Excel (.xlsx) format, do File > Save As > CSV UTF-8 before uploading.
Step 2: Run it through a validation tool
Upload your CSV to an email verification service like Extras Emporium Email Verifier. It checks each address against syntax rules, DNS and MX records, disposable domain databases and typo patterns, then asks the recipient's mail server whether the mailbox actually exists — without sending any email. Within minutes, you get three clean buckets: send_safe, risky and invalid.
Step 3: Remove or segment risky addresses
Delete all addresses in the "invalid" bucket. For "risky" addresses (catch-all domains, role-based emails like info@), either remove them or move them to a separate segment with lower sending frequency. Only send your main campaigns to the "send_safe" list.
Step 4: Make it a habit
Clean your list before every major campaign, and at minimum once per quarter. Email addresses decay at a rate of about 22% per year — people change jobs, abandon accounts, and domains expire. Automated validation before each send ensures you maintain a bounce rate under 1%.