Import n8n-lead-email-cleanup.json into a NEW workflow. Click Execute workflow. Open Check demo results: expect PASS, input 5, ready 2, duplicates 1, review 2. No credentials, paid API or external calls required. The sample uses fictional .example addresses. Clean and flag emails keeps every row; filter status=ready before a live integration. Duplicate checks only cover one incoming batch. Use a CRM lookup/upsert or durable unique key for duplicates across runs. Check demo results is only for the five supplied fixtures; remove it when changing the input. Lowercasing is a practical CRM convention, not proof that every mail provider treats addresses identically. Format checks do not prove deliverability. No Gmail dot or plus-address rewriting.