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Real-world workflow

Use Case

Dedupe an Email List Before a Campaign

Remove duplicate email addresses before importing to a mailer — keep first occurrence, optional case-insensitive match.

14 August 2026 By Tools.Town Team 5 min read

The problem

Merged CRM exports and event signups create duplicate addresses. Importing them wastes sends and annoys subscribers.

Steps

  1. Export addresses as one email per line.
  2. Open Remove Duplicates from List.
  3. Prefer case-insensitive so Pat@x.com and pat@x.com collapse.
  4. Optionally enable Trim lines.
  5. Copy uniques into your mailer.
  6. For A/B tests, send the clean list to List Splitter → Into K groups → K=2.

Frequently Asked Questions

Does this validate emails?

No — it only removes duplicate lines. Validate addresses separately before send.