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MailGuard

Guide

How to clean an email list before sending.

A clean list is smaller, more accurate, and less likely to cause bounces. Here's a process you can repeat every time.

Verify your first list View pricing

No monthly subscription · Credits never expire · Unknown results use no credits

Why list cleaning matters

Lists decay naturally. People change jobs, abandon personal inboxes, and mistype addresses on forms. Every invalid address you send to is a potential bounce, and a pattern of bounces can make mailbox providers more cautious about your mail.

Cleaning before a campaign is the easiest way to avoid this. It takes minutes and costs a fraction of what a damaged sender reputation would.

Before you start

  • Export the list from your email platform or CRM as CSV
  • Keep a backup of the original file
  • Note where each segment came from, such as sign-up forms, events, or imports

Deciding what to keep

Passed addresses are safe to keep. Failed addresses should be removed or suppressed. Unknown addresses need judgment: keep the ones that came from real sign-ups, and consider dropping the ones from older or unknown sources.

Disposable domains and role accounts like info@ or sales@ are flagged in the details. Whether to keep them depends on your use case.

Keeping the list clean afterwards

  • Use double opt-in on sign-up forms
  • Remove hard bounces automatically after each send
  • Re-verify segments that haven't been mailed in 3+ months
  • Never mix purchased contacts into permission-based lists

What MailGuard can help with

  • Checking single addresses or bulk CSV/TXT lists before a campaign
  • Sorting each address into Passed, Failed, or Unknown, with a plain-language reason
  • Flagging disposable domains, role accounts, syntax issues, and catch-all behavior
  • Exporting a filtered list that contains only the results you choose
  • Paying only for Passed and Failed results, since Unknown results use no credits

Limitations

Verification reduces uncertainty before sending. It does not guarantee inbox placement and does not replace consent or list hygiene.

Verification can't tell whether a person wants your email, and a mailbox that passes today can close tomorrow.

Step by step

  1. 1

    Export your list

    Download your contacts as a CSV or TXT file.

  2. 2

    Upload to MailGuard

    Start a bulk verification job. Duplicates are removed automatically.

  3. 3

    Review results

    Look at Passed, Failed, and Unknown counts and read the reasons.

  4. 4

    Filter and export

    Download the results and keep only the addresses you trust.

  5. 5

    Re-import and suppress

    Re-import the clean list and suppress Failed addresses in your platform.

Frequently asked questions

How long does list cleaning take?

Small lists finish in minutes. Larger lists take longer depending on how quickly receiving servers respond.

Will I lose real subscribers?

Failed addresses can't receive mail anyway. Review Unknown addresses carefully instead of deleting them all.

Related

Ready to check your list?

Pay only for Passed and Failed results. Credits never expire.

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