Case Study: Email List Cleaning & Validation for Client Retargeting

The Challenge

The client approached our consulting firm with a stagnant email list of ~500 addresses. Over time, the list had become outdated due to staff turnover, domain changes, and inactivity.

Email List Management

Key concerns:

• High bounce rates on previous campaigns

• Fear of damaging sender reputation

Client Overview:

Client Type: Medical Device Inventor

Industry: Medical Device Marketing to PE/VC

Location: Louisville, KY

List Size: 500 emails

Project Scope: Email List Cleaning & Testing for Future Marketing Use

Our Process:

1. List Analysis

We began with a structural and quality audit of the email list.

Steps Taken:

• Checked formatting issues (e.g., typos in domains like “gamil.com”)

• Removed duplicate entries

• Assessed domain health and common providers (e.g., corporate vs. free email domains)

Result: Identified 16 syntactically invalid or malformed addresses

2. Email Validation & Cleaning

Next, we used professional email verification tools (such as ZeroBounce and NeverBounce) to assess deliverability.

Validation Metrics:

• Syntax errors

• Disposable/temporary emails

• Role-based accounts (e.g., info@, sales@)

• Bounce risk (hard/soft)

Result:

• Removed 34 additional emails flagged as dead, invalid, or high-risk

• Final cleaned list: 450 verified emails

3. Test Campaign Execution

To ensure real-world deliverability, we conducted a test email campaign to the validated list of 450.

Testing Goals:

• Confirm inbox placement

• Monitor bounce rate

• Track engagement (opens/clicks)

Email Content: A simple brand reminder with no promotional content, personalized to avoid spam flags.

Results:

• 0 hard bounces, One soft bounce

• 17% open rate (indicating active and reachable inboxes)

• Spam complaints: Zero

• Delivery time: Under 30 minutes for all recipients

4. Final Handoff

We delivered a cleaned, validated, and tested list to the client in CSV format, complete with:

• Deliverability status for each email

• Recommendations for ongoing list hygiene

Outcome & Impact:

✅ The client regained confidence in their email list

✅ List is ready for use in future nurturing and sales campaigns

✅ Protected sender reputation for future mailouts

Client Testimonial

“We didn’t realize how much dead weight was in our email list. The Xolotech team’s process was clear and fast. We now have a clean list we can trust.”

— Owner, Medical Device Invention

Summary

Metric	Result
Initial Email Count	500
Invalid/Dead Emails Removed	50 (10%)
Final Verified Emails	450
Bounce Rate (Test Campaign)	< 1%
Open Rate (Test Campaign)	17%

Want to Clean Your Email List?

Xolotech helps small businesses protect their deliverability and maximize engagement through trusted data hygiene practices.

~ Xolo

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