How to clean an email list
Cleaning an email list means removing the addresses that will bounce or harm your sender reputation, and setting aside the ones you are unsure about, before you send. A practical method has six steps: export, deduplicate, verify, segment, suppress and repeat.
1. Export the list
Export from your email platform or CRM as CSV, with the columns you will want to re-import (an id, the address, consent fields). Keep the export: you will match results back to it.
2. Remove obvious duplicates
Addresses that differ only in letter case reach the same mailbox in practice. A verification service does this for you: email-validation.org removes duplicates inside a job and charges each unique address once, and every duplicate row still gets the result.
3. Verify every address
Upload the file as a bulk job. Each row gets a status, a reason and a recommended action. Malformed addresses, duplicates and unknown results cost nothing.
4. Segment by result
| Result | What to do |
|---|---|
deliverable | Keep. Watch low_engagement addresses in campaigns. |
risky – catch-all, role and forwarding reasons | Keep in a separate, carefully sent segment. See catch-all emails. |
risky – disposable, toxic, suppressed, traps, complainers | Remove. |
undeliverable | Remove, and fix typos where did_you_mean suggests a correction you can confirm. |
unknown | Keep aside and re-check later; many become definite on a second check. |
The action column (ev_action in the result file) applies this for you: send, send_with_caution, remove or retry_later.
5. Suppress, do not just delete
Put removed addresses on a suppression list in your sending platform. Otherwise they come back with the next import or form sync, and you pay to discover the same problem again.
6. Repeat on a schedule
People change jobs and abandon mailboxes, so lists decay even when nothing is added. Verify:
- new addresses as they arrive, at sign-up or import;
- the whole list before a large or unusual send;
- segments you have not mailed for a few months, before mailing them again.
Keep consent separate
Verification tells you whether mail can arrive, not whether the person agreed to receive it. Never use verification to make a purchased or scraped list usable; our acceptable use policy forbids it.
Related
How we wrote this: drafted by the email-validation.org team with the help of AI writing tools, from our product documentation and the sources linked in the text.