Let’s be honest: most people’s contact lists are a mess—duplicates, outdated emails, and all sorts of junk that’ll kill your outreach. If you’re using Warmuphero to warm up inboxes and send campaigns, clean data isn’t just “nice to have”—it’s the difference between hitting inboxes and landing in spam. This guide walks you through importing and cleaning your contacts in Warmuphero, minus the fluff and empty promises.
If you want practical steps that actually work (and a few things to skip), you’re in the right place.
Step 1: Prep Your Contact List Before Importing
Don’t just dump your raw CSV into Warmuphero and hope for the best. Garbage in, garbage out. The cleaner your list, the fewer headaches you’ll have later.
What to do before uploading:
- Start fresh: Use a spreadsheet tool like Google Sheets or Excel.
- Stick to the basics: Have at least “Email” as a column. Add “First Name,” “Last Name,” “Company,” etc. only if you’ll actually use them in your outreach.
- Remove obvious junk: Delete any rows that are missing emails, or have weird formatting (no @ symbol, etc).
- Check for duplicates: Most spreadsheet tools have easy ways to highlight and remove duplicate email addresses.
- Avoid role-based addresses: Emails like info@, sales@, or support@ aren’t likely to reply and might hurt your sender reputation.
- Don’t upload people who opted out: If someone unsubscribed or asked to be removed, respect it. It’s not just ethical—it’s the law.
Pro tip: If your list is old, run it through a free email validator tool before importing. You’ll catch a lot of dead or risky addresses that way.
Step 2: Format Your CSV for Warmuphero
Warmuphero needs a clean CSV (comma-separated values) file to import contacts. Here’s what matters:
- First row is headers: “Email”, “First Name”, etc.
- No blank columns: Delete any empty columns, especially at the end.
- UTF-8 encoding: Most tools default to this, but double-check if you’re getting weird character errors.
- No formulas: Only raw text values—formulas can break the import.
What works: Keeping it simple. Just have the columns you need, in plain text.
What doesn’t: Copy-pasting from random sources like Outlook exports, which can add hidden formatting and garbage data. Always open your file in a spreadsheet and check.
Step 3: Import Contacts into Warmuphero
Now you’re ready to bring your list into Warmuphero.
Here’s how to do it:
- Log in to your Warmuphero dashboard.
- Find the “Contacts” or “Lists” section. (Warmuphero sometimes updates its UI, but look for “Import” or “Add Contacts.”)
- Click “Import” and select your CSV file.
- Map your columns. Warmuphero will ask which column is “Email,” “First Name,” etc. Double-check these.
- Review the import preview. Make sure the data lines up—no emails in the “Company” column or vice versa.
- Start the import. Wait for it to finish. If there are errors, Warmuphero will usually flag them (invalid emails, missing required fields, etc.).
Honest take: The import process is usually smooth, but if your CSV is messy, expect errors. Don’t panic—just fix the file and try again.
Step 4: Clean Contacts Inside Warmuphero
Warmuphero does some automatic checks, but don’t rely on software alone. If you want high deliverability, spend a few minutes tidying up.
Do this after import:
- Remove obvious bounces: Warmuphero will sometimes flag emails that look risky or have bounced before. Delete or suppress these.
- Tag or segment: If you have different types of contacts (customers vs. prospects), assign tags or lists so you can personalize later.
- Spot-check random entries: Scroll through a few pages. If you see weird names (“asdf@asdf.com” or gibberish), clear them out.
- Check for duplicates again: Most tools catch these, but double-check, especially if you imported multiple lists.
What to ignore: Don’t obsess over every single field. If all you need is the email, extra columns aren’t hurting anything.
Step 5: Validate and Warm Up (Optional, But Smart)
You don’t have to validate every email, but if your bounce rate is high, your sender reputation tanks. Some folks skip this and pay the price.
Two options:
- Use Warmuphero’s built-in validation (if available): Some plans include email verification. Use it if you can.
- Try a third-party validation tool: Services like NeverBounce or ZeroBounce can scrub out dead addresses. Export your list, validate it, re-import clean contacts.
Pro tip: If you’re importing thousands of emails, do a test send to a small batch first. If you see lots of bounces or spam complaints, stop and clean up.
Step 6: Manage Opt-Outs and Compliance
Warmuphero helps with unsubscribe handling, but you need to respect opt-outs from day one.
- Import your suppression list: If you have a list of people who unsubscribed or complained in the past, import them as a “do not contact” list.
- Regularly clean unsubscribes: Check your reports and remove anyone who opts out.
- Be cautious with purchased lists: Honestly, don’t use them. They’re usually more trouble than they’re worth—low engagement, high complaints, and can get you blacklisted.
Step 7: Maintain and Update Your List
A clean list isn’t a one-and-done task. Make it a habit:
- Run periodic validations: Every few months, check for dead or bouncing emails.
- Remove inactive contacts: If someone hasn’t opened or replied in ages, consider moving them to a re-engagement campaign or dropping them.
- Keep data minimal: Only collect and store what you actually need. More data means more to maintain—and more risk.
What Actually Matters (And What Doesn’t)
After working with a lot of lists and tools, here’s what’s worth your time:
Matters: - Valid emails (no typos, no role addresses) - Recent, opted-in contacts - Clean formatting (no hidden junk) - Respecting unsubscribes
Doesn’t matter much: - Fancy personalization fields you never use - Over-tagging or micro-segmenting your list - Uploading every old contact you’ve ever met
Keep it simple and focused. The best outreach comes from clean, targeted lists—not bloated databases full of ghosts.
Wrapping Up: Keep It Simple, Iterate Often
Importing and cleaning contact lists in Warmuphero isn’t rocket science, but it does take a little discipline. Don’t overcomplicate it—just start with a clean CSV, double-check as you go, and prune your list regularly. The cleaner your data, the better your outreach will perform. And if something’s not working, don’t be afraid to step back, tidy up, and try again. That’s how you keep your outreach sharp—and out of the spam folder.