If you’re running go-to-market (GTM) campaigns and your emails aren’t getting through, you’re burning money. It’s not glamorous, but cleaning up your email lists makes everything work better—higher deliverability, fewer bounces, and less chance you’ll end up in the spam folder. This guide is for marketers, sales ops folks, and anyone who wants to squeeze more out of their email by actually reaching real people. Let’s break down how to actually use Zerobounce reports so they’re more than just a CSV you ignore.
1. Why Email Validation Matters… and What to Ignore
Before you start poking at reports, let’s be clear about what email validation can and can’t do:
- What it’s great for:
- Cutting fake, dead, or risky emails that tank your sender reputation.
- Reducing bounces that make ESPs (like Google and Microsoft) hate you.
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Helping you focus on emails that might actually convert.
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What it won’t fix:
- Bad copy, irrelevant offers, or lists full of people who never wanted your emails in the first place.
- Deliverability issues from shady past practices—validation is a filter, not a magic eraser.
Pro tip: Don’t obsess over “perfection.” No list is 100% clean, and that’s fine. The goal is to stop shooting yourself in the foot.
2. Get Your Zerobounce Report: Don’t Skip the Basics
Most folks upload a list, run validation, and download the spreadsheet. That’s the easy part. If you haven’t done it yet, here’s the quickest path:
- Export your email list from your CRM or marketing platform.
- Make sure it’s a CSV or TXT. Zerobounce likes those.
- Upload to Zerobounce.
- Drop in your file, hit validate.
- Download your results.
- You’ll get a file (CSV/Excel) full of columns you may or may not care about.
It’s tempting to just delete the “Invalid” addresses and move on. That’s better than nothing, but you can do a lot more.
3. Make Sense of the Key Zerobounce Columns
Zerobounce spits out a lot of data. Not all of it matters. Here are the columns you should actually care about:
- Email Address:
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Obvious, but double-check for typos or weird formatting issues.
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Status:
- The big one. Usually shows: “Valid”, “Invalid”, “Catch-All”, “Do Not Mail”, “Spamtrap”, “Unknown”.
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What these mean:
- Valid: Safe to send.
- Invalid: Dead or fake—delete these.
- Catch-All: This is a wildcard domain that accepts anything. Risky—see below.
- Do Not Mail: Role accounts (e.g. info@, admin@) or known spam traps. Avoid.
- Spamtrap: Don’t send. Ever.
- Unknown: Couldn’t verify—treat with caution.
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Sub-status:
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Sometimes gives more detail (like “disposable”, “toxic”, “role-based”).
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Account Status / First Name / Last Name / Gender / Location:
- Nice-to-haves, but don’t use these to decide whether to send. They’re mostly for enrichment.
Columns to ignore:
Anything you don’t understand and can’t use. Don’t get fancy with “MX Found” or “SMTP Provider” unless you’re truly technical.
4. What to Do With Each Result Type
Here’s the practical bit: what you should actually do with each status.
Valid
- Keep.
- These are the emails you want to send to. If you’re trimming, these stay.
Invalid
- Delete or suppress.
- Remove from your master list. Sending here is a waste and will hurt you.
Catch-All
- Be careful.
- These addresses might be valid, or the domain just accepts all mail. Some will bounce.
- If your sender reputation is strong and you’re sending personalized, low-volume campaigns, you can risk these.
- For big blasts or if you’ve had deliverability issues, skip them.
Do Not Mail / Role-based (info@, support@, etc.)
- Suppress.
- Most don’t convert, and they’re often monitored by anti-spam traps. Some exceptions for B2B, but generally not worth it.
Spamtrap
- Never send.
- These addresses exist solely to catch spammers. One hit, and your domain will get flagged.
Unknown
- Decide based on risk.
- Sometimes mail servers won’t confirm if an address exists. If you have budget for a few bounces and need volume, you can try—but keep an eye on bounce rates.
5. Cleaning and Segmenting Your List (The Real Payoff)
Don’t just delete “Invalid” emails and blast everyone else. Use the report to actually segment for better results.
A simple workflow:
- Remove Invalid, Spamtrap, and Do Not Mail emails.
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Don’t overthink it; just get rid of them.
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Separate Catch-All and Unknown into their own list.
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Send only if you’re comfortable with a slightly higher bounce rate.
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Tag role-based emails (info@, admin@).
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Send only if you have a good reason (e.g., B2B with no other contact).
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Keep Valid as your “gold” segment.
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Use this for your main campaigns.
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Optionally, enrich with other useful columns.
- If you want to get fancy, use first name, company, or location to personalize.
Pro tip:
If you’re syncing with a CRM, make sure you update existing records instead of just adding new ones. Otherwise, you’ll end up with duplicates or keep emailing junk.
6. Tracking Your Results and Iterating
Validation isn’t a one-time job. Here’s how to keep your list in shape:
- Regularly re-validate:
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Emails go bad fast—up to 22% of lists degrade every year. Run new lists through Zerobounce every quarter, or before any big send.
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Monitor bounce and spam complaint rates:
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If you’re still getting high bounces after cleaning, look at your sources—maybe your list-building’s the problem.
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Watch for “Unknown” trends:
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If you’re seeing a lot more “Unknown” or “Catch-All,” it might be a sign that domains are using more aggressive filtering or hiding. It happens.
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Don’t be afraid to prune:
- If an address hasn’t opened an email in a year, consider removing it—validated or not.
Ignore:
- Chasing down every “Unknown” is a waste of time. Focus on the 80% that’s clear and actionable.
7. Common Mistakes and Myths
Here are the traps people fall into:
- Assuming validation = deliverability.
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Not true. Validation is step one. Your sending practices, content, and reputation matter more.
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Panic over a few bounces.
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Every list has some. If you’re under 2% bounce rate, you’re fine.
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Treating role accounts like gold.
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They almost never convert and sometimes get you flagged.
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Skipping regular validation.
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“One and done” doesn’t work. Lists age.
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Ignoring reporting tools from your ESP.
- Use insights from Mailchimp, HubSpot, or whoever you send from. If they say you’re getting flagged, believe them.
8. Quick Wins: What to Do Next
If you want to see results fast:
- Run your list through Zerobounce right now.
- Delete or suppress everything marked Invalid, Spamtrap, or Do Not Mail.
- Segment out Catch-All and Unknown. Send cautiously.
- Update your CRM and marketing tools with the clean list.
- Set a reminder to re-validate in 3-6 months.
Keep It Simple, Iterate Often
There’s no bonus points for perfect data. Just clean your list, send to real people, and repeat. Don’t get lost in the weeds—most of the value comes from just cutting the junk and sending with confidence. If you keep it simple and revisit your process every quarter, the rest of your GTM engine will run smoother.