# Keeping your audiences healthy

> Remove bounces and unsubscribes, re-engage or drop inactive contacts, and watch your complaint rate. A clean list is the foundation of inbox placement.

**List hygiene** is the ongoing work of keeping your audiences full of valid, engaged, consenting recipients. It's the highest-leverage thing you can do for deliverability: a clean list lowers bounces and complaints, raises engagement, and keeps mailbox providers trusting you. A neglected list does the opposite, slowly, until your mail starts landing in spam.

## Remove bounces and unsubscribes

MailBlastr does most of this automatically: hard bounces, complaints, and unsubscribes are added to your account-wide [suppression list](https://www.mailblastr.com/docs/kb/suppression-list) and skipped on every future send. But suppression hides bad addresses from sending — it doesn't prune your source data.

- Periodically clean the **source** of your contacts (your CRM, signup database) so you stop importing addresses that will just bounce.
- Don't re-add or re-import addresses that previously bounced or complained — you'll just re-suppress them and waste reputation.
- Treat the suppression list growing fast as a warning sign that your acquisition is letting in bad or non-consenting addresses.

> **Note:** Suppression and unsubscription are different. MailBlastr auto-**suppresses** sends to bounced and complained addresses, but it does not automatically **remove** that contact from your audience. Use a [bounce / complaint webhook](https://www.mailblastr.com/docs/webhooks/overview) to proactively unsubscribe or prune those contacts at the source so your audience counts and segments stay honest.

## Collect valid addresses in the first place

The cheapest hygiene is not letting bad addresses onto the list at all:

- **Block bots with CAPTCHA at signup.** Bots sign up freely and fill your list with fake addresses that bounce. A challenge such as Google reCAPTCHA, hCaptcha, or Friendly Captcha keeps signups human.
- **Use double opt-in.** Send a confirmation link the subscriber must click before they're added — this verifies the address is real *and* that its owner wanted in, and supports CAN-SPAM / CASL compliance.
- **Verify deliverability with a third-party service.** Valid *syntax* (RFC 5322) doesn't mean a live inbox; an address-verification service flags addresses likely to bounce before you ever mail them.

## Re-engage, then sunset, inactive contacts

Contacts who never open, click, or reply drag down your engagement signals — and low engagement is itself a spam signal. Major providers like Gmail and Microsoft expect you to mail people who've recently engaged, so as a rule of thumb limit non-transactional sends to contacts who **opened or clicked within the last 6 months** (adjust for your industry and cadence). Don't keep mailing dead weight forever.

1. **Identify the inactive** — Find contacts with no clicks or replies over a meaningful window (e.g. the last 3–6 months). Lean on clicks and replies rather than opens, which are noisy.
2. **Run a re-engagement campaign** — Send a short "do you still want to hear from us?" message with a clear way to stay subscribed.
3. **Sunset the rest** — Stop mailing — or unsubscribe — contacts who don't re-engage. A smaller, engaged list outperforms a big, dead one on both placement and results.

> **Note:** Opens are unreliable — corporate scanners and webmail image proxies (and Apple Mail Privacy Protection) fetch the tracking pixel. MailBlastr filters scanners and delivery-time prefetches out of your counts, but for engagement decisions, **clicks and replies are stronger signals than opens**.

## Monitor your complaint rate

A rising complaint rate is the clearest early warning that a list or a campaign is unwelcome. Keep complaints under **0.1%** where you can; treat 0.3% as a red line. If complaints climb, pause, look at what changed (a new segment? a bought list? a tone shift?), and fix the source.

## Hygiene checklist

- Only add contacts with explicit [consent](https://www.mailblastr.com/docs/kb/consent).
- Let MailBlastr auto-suppress bounces, complaints, and unsubscribes — and don't fight it by re-importing them.
- Review engagement quarterly; re-engage or sunset the inactive.
- Watch bounces and complaints on every campaign in your [logs](https://www.mailblastr.com/docs/logs/overview).
- Keep volume steady and warm up new domains — see the [warm-up guide](https://www.mailblastr.com/docs/kb/warm-up).