How to clean your email list, step by step
A practical, ordered process for cleaning an email list: back up, deduplicate, verify, segment and keep it clean afterwards.
Photo by theglassdesk on Pixabay
A clean list is the cheapest deliverability improvement you can make. Here is a process you can follow in an afternoon.
1. Export and back up
Export your list from your email platform as a CSV and keep an untouched copy. You will be removing rows, and you want to be able to compare afterwards.
Include whatever engagement data you have: signup date, last open, last click, source.
2. Remove obvious junk
Before you pay for any verification, drop the rows that are clearly wrong:
- blank addresses
- exact duplicates (ignore case:
Sam@x.comandsam@x.comare the same address) - test entries like
test@test.com
A spreadsheet's remove-duplicates function handles most of this. Our CSV preparation tips go deeper.
3. Verify the list
Upload the file to a verification service. You get back a status for every row. With Mailsure that is valid, risky, invalid or unknown, plus a score and a reason.
Duplicates are free to upload with us, so you can skip step 2 if you are short of time.
4. Act on each status
| Status | Meaning | What to do |
|---|---|---|
| valid | Looks deliverable | Keep |
| invalid | Will bounce | Delete |
| risky | Deliverable but doubtful (disposable, role account, probable typo, catch-all) | Segment, decide case by case |
| unknown | Couldn't be checked right now | Retry later, or send with care |
For addresses with a typo suggestion, fix them rather than deleting: sam@gmial.com is probably a real person who is still waiting for your email.
5. Segment the risky group
Don't send risky addresses with your main list. Send a smaller test to them first and watch the bounce rate. Role accounts like info@ often belong to a business you do want to reach, but expect lower engagement.
6. Re-import and suppress
Upload the cleaned list back and add the invalid addresses to a suppression list so they can't be re-added by a later import.
7. Keep it clean
- Verify new signups in real time through the API.
- Re-verify before big campaigns (how often to clean).
- Retire people who never engage.
Then send, and compare your bounce rate with your last campaign. That comparison is how you know the cleaning worked.
