What is a recycled spam trap?
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A recycled spam trap is an email address that used to belong to a real person, got abandoned, and was later converted into a trap by a mailbox provider. The address goes through a cooling-off period (usually several months to a year) where it hard bounces with errors like "550 User Unknown." After that grace period, the provider quietly reactivates it as a spam trap. If you're still sending to it, you just told every spam filter that you don't clean your list or honor bounces.
Why this exists: mailbox providers (like Gmail, Outlook, Yahoo) want to catch senders who keep mailing dead addresses. It's a filter for lazy list hygiene. If an address has been bouncing for six months and you're still hitting it, you're either buying lists, scraping emails, or ignoring your own bounce reports. All bad signals.
The practical damage: hitting a recycled trap tells spam filters you have poor list management. Your sender reputation drops. Your emails start landing in spam, sometimes across your entire domain. The scary part is you can't tell which addresses are traps just by looking at them. They look like normal bounces until they stop bouncing.
How they get on your list: someone signed up years ago, stopped using that address, and you kept mailing them. Or you bought a list (please don't) that included old addresses. Or you inherited a list from a previous team who never cleaned it. The longer your list sits without hygiene, the more likely you have recycled traps hiding in it.
What you should do: remove hard bounces immediately (within 24 hours). Set up a sunset policy to remove subscribers who haven't opened or clicked in 6-12 months. Run your list through validation (we clean them, if you're stuck ;)) to catch addresses that used to bounce but might be reactivated. If your ESP doesn't auto-suppress hard bounces, that's a red flag about your ESP.
Not sure if you have recycled traps? Check your bounce rate over the past year. If you see addresses that bounced for months and then stopped bouncing without you removing them, that's suspicious. Also check how long your oldest inactive subscribers have been on your list. If you have people who haven't opened an email in two years, you're at risk.
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