How-To Guides for Verifying and Cleaning Email Lists
Ten step-by-step tutorials covering the places email lists actually live: spreadsheets, Mailchimp and HubSpot, your own signup form, and your DNS records. Each one names the menus, the record syntax and the decisions you have to make along the way.
Every page in this section is a procedure. Where the glossary defines what a term like catch-all or spam trap means, and the use case pages describe situations where verification pays off, these guides tell you which button to press: the exact Mailchimp menu path, the DNS record syntax, the API header, the spreadsheet formula that merges results back into your original file. They assume you have already decided to clean your list and now need to do it without breaking anything. If you are still deciding, read a use case first and come back here when you want the steps.
Underneath the platform differences, almost all of these guides follow the same four moves: export the list, run it through the bulk email verifier, act on the returned statuses, and put the clean list back. What changes between platforms is the export menu, the import mapping, and what removal actually means — in Excel it is a filter and a delete, in Mailchimp it is an archive that preserves subscriber history, in HubSpot it is a custom property that keeps the contact record intact for your sales team. Learn the shape of the workflow once and each platform-specific guide becomes mostly a map of menus.
The results you get back are not a simple pass or fail, and these guides are written around that. Invalid and disposable addresses are easy calls: remove them. Risky and catch-all results are judgment calls that depend on the bounce rate you are already carrying and how much a given contact is worth to you, which is why the pre-campaign guide gives you thresholds rather than a rule. Spam traps are harder still, because they never bounce and no provider publishes their addresses, so removing them is a matter of stripping out high-risk patterns rather than identifying individuals.
Be honest with yourself about which of these are finished when you finish them. Setting up SPF, DKIM and DMARC and adding real-time verification to your signup path are DNS and engineering jobs you complete once, and afterwards only touch when you add a new sending service or a new form. Cleaning a Mailchimp audience, a HubSpot database or a spreadsheet is maintenance, and how fast it comes back is decided by how addresses get in: a list fed by an unguarded form re-dirties itself faster than any cleaning schedule can keep pace with. That is why the two categories are not independent, and why the order matters — do the prevention work first and each cleanup after it is smaller than the one before, instead of the same rescue job repeated forever.
Start with the list in front of you
Most lists live in a spreadsheet before they live anywhere else, and both guides here work from an export rather than an integration. The Excel walkthrough covers removing duplicates before you upload, filtering by status afterwards, and using VLOOKUP or XLOOKUP to merge verification results back into the original file without losing your other columns. The Google Sheets guide adds a second route: an Apps Script function you can call as a formula in a cell for small lists, with the six-minute execution limit and safe API key storage handled properly.
- Verify Email in Excel Excel email verification workflow.
- Verify Email in Google Sheets Google Sheets verification.
Clean the platform that owns your contacts
Once contacts live in a marketing platform or CRM, deleting them is rarely the right move — you lose history, reporting accuracy and, in a CRM, sales context. These two guides show the safer path: archiving in Mailchimp, which drops contacts out of your billable count while preserving their record, and creating an email verification status property in HubSpot so you can exclude bad addresses from workflows and active lists without touching the contact itself.
- Clean Mailchimp List Mailchimp list cleaning steps.
- Clean HubSpot Contacts HubSpot contact cleaning.
Stop bad addresses at the door
Cleaning is reactive; this is the preventive work that stops you having to do it as often. The API guide covers authentication, the status and score fields you get back, the error codes worth handling explicitly, batch requests for volume, and the sandbox header for development. The signup form guide applies the same check at the point of entry, including why you should still validate server-side when you already validate in the browser, and what error copy actually helps someone fix a typo instead of abandoning the form.
- Verify Email with API API integration code.
- Add to Signup Form JS/HTML form integration.
The routine before every send
These are the two checks that belong in your pre-send process rather than in a quarterly cleanup. The pre-campaign guide is a checklist you run a day or two before launch, including how to treat risky and catch-all results depending on the bounce rate you are already carrying, and why a seed test across several inbox providers comes before the full send. The spam trap guide covers the threat that produces no bounce and no warning at all, and is built around removing the patterns that harbour traps — never-engaged contacts, purchased data, typo domains — since individual traps cannot be identified.
- Verify Before Campaign Pre-campaign workflow.
- Remove Spam Traps Spam trap removal steps.
Fix the underlying deliverability problem
If you have cleaned your list and mail still goes to spam, the problem sits upstream of your contacts. The bounce rate guide treats getting under 2% as an ongoing programme rather than a single cleanup: audit, verify, switch to double opt-in, monitor every campaign, re-verify on a schedule. The authentication guide is the one-off DNS job behind all of it, walking through SPF includes and lookup limits, DKIM key generation and selectors, and the staged DMARC rollout from p=none through quarantine to reject — each of which you can confirm with the SPF, DKIM and DMARC checker.
- Reduce Bounce Rate Below 2% Bounce rate reduction steps.
- Setup SPF DKIM DMARC DNS record setup steps.
Nearly every guide here begins the same way — export your list and run it through the bulk verifier, then follow the platform-specific steps for putting the clean version back.
Start a bulk checkHow-To FAQ
Start with wherever your list physically lives today, because that determines the export step. If it is a spreadsheet, begin with the Excel or Google Sheets guide; if it is already in a marketing platform, begin with the Mailchimp or HubSpot guide; if addresses arrive through your own product, the signup form and API guides will save you the most work over time. If your mail is currently landing in spam rather than bouncing, skip the cleanup guides for now and set up SPF, DKIM and DMARC first, because no amount of list hygiene fixes an authentication failure.
Quarterly is the usual cadence for a Mailchimp or HubSpot cleanup, but the interval is really set by intake and age: a database that has taken on thousands of new contacts since the last pass needs attention sooner than one that has barely moved. The pre-campaign check does not sit on a calendar at all — run it 24 to 48 hours before the send, close enough that the results are still current when the mail actually goes out, and run it for every campaign. DNS work is triggered rather than scheduled: you go back to your SPF record when you add a sending service, and you return to DMARC after two to four weeks of reading aggregate reports, when you are ready to move from p=none to quarantine. The API and signup form integrations have no cadence of their own; they either keep running or they fail loudly enough for you to notice.
No, and several of these guides deliberately stop short of telling you to. Invalid, disposable and suspected spam trap addresses should come out in every case, since sending to them can only cost you. Risky and catch-all results are a judgment call: if your bounce rate is already close to the 2% line, exclude them from the next send, and if it is comfortably below that you can keep them under monitoring or route them through a re-engagement sequence first. In a CRM, tagging an address with a verification status is almost always better than deleting the record it belongs to.