If you’re in sales and sick of seeing your emails bounce, you’re not alone. Nothing kills outreach momentum faster than sending to dead or dodgy addresses. Worse, too many bounces can land your team in spam folders, tank your sender reputation, and waste your time.
This guide walks you step-by-step through cleaning your email lists with Zerobounce. No fluff, no hype—just the process that actually works if you want real results.
Why Bother Cleaning Your Email List?
Let’s be blunt: Emailing a dirty list is like cold-calling disconnected numbers. Here’s what happens if you skip cleaning:
- More bounces: ESPs (like Gmail) start to notice and might block you.
- Wasted effort: You’re pitching to ghosts and bots.
- Lower deliverability: Even your good emails might go to spam.
- Reputation hit: Eventually, you could get blacklisted.
So, if you care about reaching real prospects (and keeping your job), cleaning is not optional.
Step 1: Export Your Email List
Before you can clean anything, you need your list in a usable format.
What to do: - Export your leads or contacts from your CRM or whatever tool you use (Salesforce, HubSpot, Outreach, Sheets, etc.). - Save as a CSV file. Zerobounce likes CSVs best.
Pro tips: - Make sure each email is in its own column, preferably labeled "Email." - Remove duplicate emails before uploading. Zerobounce will flag them, but it’s faster to do it yourself.
Step 2: Create a Zerobounce Account (If You Don’t Have One)
If you’re already set up, skip ahead. If not:
- Go to Zerobounce and sign up—yes, they’ll want your email. They have a pay-as-you-go option, so you don’t need a subscription to get started.
- Confirm your account via the email they send you. (Irony: if you don’t get it, check your spam.)
Heads up: Zerobounce gives you a handful of free credits to test, but you’ll need to pay for large lists. Pricing is public and no, it’s not the cheapest tool out there—but it’s reliable.
Step 3: Upload Your List to Zerobounce
Here’s where the magic happens.
- After logging in, go to the “Email Validation” section. Click “Upload File.”
- Drag and drop your CSV, or select it from your computer.
- Zerobounce will ask you to map columns. At minimum, map the one with emails.
What to ignore: - You don’t need to upload first names, last names, company names, etc. Only upload what’s needed. Less is more.
Pro tips: - If you have a huge list (like 50,000+), break it into chunks. Processing can slow down or stall with massive files.
Step 4: Start the Validation Process
Once your file is uploaded and mapped, hit “Validate.”
What happens next: - Zerobounce checks each email for validity, spam traps, abuse, temporary addresses, and more. - Processing time depends on your list size. For 10,000 emails, expect a few minutes. For 100,000+, grab a coffee.
Don’t freak out: The progress bar can seem stuck, but just let it run. Refresh only if it’s truly frozen for 30+ minutes.
Step 5: Download Your Results
When Zerobounce is done, you’ll get an email and a dashboard notification.
- Click to download your “results” file. It’ll be a CSV.
- Each row has your original data, plus new columns like “Status” (Valid, Invalid, Catch-All, Spam Trap, etc.).
What you care about: - Valid: Safe to send. - Invalid: Remove these from your outreach—these are dead. - Catch-All: Risky. Some companies have catch-all domains, so Zerobounce can’t confirm if the address exists. Sending to these is a gamble. - Spam Trap/Abuse/Do Not Mail: Definitely remove these. These are toxic.
Step 6: Clean Up Your List
Open your results CSV in Excel or Google Sheets.
- Filter by the “Status” column.
- Keep only “Valid.”
- Delete or move to a separate sheet any “Invalid,” “Spam Trap,” or “Abuse” emails.
- For “Catch-All,” it’s a judgment call. If you’re risk-averse, skip them. If you’re desperate for coverage, send—but watch bounce rates.
Why this matters: Sending to invalid or trap addresses will eventually hurt your entire domain. Don’t get greedy.
Step 7: Update Your CRM or Sending Tool
You’ve got a clean list. Now, make sure your other systems match.
- Import your cleaned, “Valid” list back into your CRM, marketing automation tool, or wherever you’re sending from.
- If possible, replace or suppress old, invalid contacts so you don’t accidentally email them again.
Pro tip: Keep an archive of the full Zerobounce results file for compliance and future reference. You might need to prove you’re not spamming.
Step 8: Rinse and Repeat Regularly
Cleaning is not a one-and-done job. Emails go stale quickly—people quit, companies rebrand, and catch-alls change.
- Best practice: Clean before any big campaign, or at least every quarter.
- If you’re adding new leads daily: Consider integrating Zerobounce’s API, so every new email is checked automatically. (Developers love this; salespeople might not care.)
What Actually Works (and What to Ignore)
Let’s clear up a few things:
- Don’t trust “free” email checkers for anything but tiny tests. They miss more than they catch.
- Don’t obsess over “Catch-All” addresses unless you’re sending at huge scale. They’re always a gray area.
- Don’t expect Zerobounce (or any tool) to hit 100% accuracy. Some bounces will slip through. That’s just email.
- Do remove bounces quickly. If your sender reputation tanks, it’s a pain to recover.
- Do keep your original lists somewhere safe. Sometimes you’ll want to revisit leads you previously cut.
Quick Troubleshooting
Problem: Zerobounce says my file is “invalid.” - Check for weird formatting—extra columns, merged cells, or odd characters can break uploads. - Make sure it’s a .csv, not .xls or .xlsx.
Problem: Processing is taking forever. - Split giant files into smaller ones. - Try uploading at off-peak hours (evenings/weekends).
Problem: Still getting bounces. - It happens. Some addresses look live but aren’t. If the bounce rate is still high after cleaning, consider double opt-in or reviewing your data sources.
Keep It Simple—and Keep Going
Sales teams get bogged down by bad data all the time. Don’t overthink it: Export, clean, filter, upload, repeat. The process isn’t glamorous, but it works. As your list grows, make cleaning a habit—not a yearly panic.
Remember: The best outreach in the world is useless if no one’s reading it. Clean lists, clear minds. That’s how you win.