A clean email list is not a one-time project - it is an ongoing process. Every campaign adds hard bounces to remove. Every month adds decay to re-verify. Every new data source adds invalids to filter. This guide covers what to remove, when to remove it, and the checklist that keeps bounce rate consistently under 2%.
| Category | Remove? | Reason |
|---|---|---|
| Hard bounces (invalid / non-existent) | Always | Permanent delivery failure. Every bounce chips away at domain reputation. Never retry. |
| Disposable emails (10minutemail, Guerrilla Mail etc.) | Always - for cold email and SaaS signup | They expire. Bounce rate from disposables compounds over time on re-used lists. |
| Spam traps | Always | Sending to spam traps leads to blacklisting. BounceZero checks known pristine and recycled trap lists. |
| Catch-all domains (for cold email) | Yes - for cold email | Catch-all servers accept all email initially. Bounce happens later when the individual mailbox rejects. Identify with BounceZero and exclude from cold sends. |
| Role-based addresses (info@, admin@, sales@) | Yes - for cold email | Not read by an individual. Low engagement and high unsubscribe rate. Fine for newsletter opt-ins where the role account is the intended recipient. |
| Unengaged newsletter subscribers (0 opens in 12 months) | Yes - for newsletters | Low engagement reduces sender reputation with ESPs that monitor it (Gmail, Outlook). Remove or run a re-engagement campaign first. |
| Soft bounces (3+ consecutive) | Yes - treat as hard bounce | After 3 consecutive soft bounces, the address is functionally invalid. Remove. |
| Opted-out / unsubscribed | Always - legally required | Required by CAN-SPAM, GDPR, CASL. Sending to unsubscribed contacts is a legal violation in most markets. |
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