Setting spam thresholds and quarantine sensitivity
Every alias in Cleanbox has two spam thresholds that control how incoming messages are handled. Understanding and adjusting these thresholds gives you fine-grained control over what lands in your inbox, what gets held for review, and what gets blocked entirely.
What are spam thresholds?
Each alias has two key settings:
- Quarantine threshold — messages scoring above this value are held for your review instead of being delivered.
- Reject threshold — messages scoring above this value are blocked outright and never delivered.
Messages that score below both thresholds are delivered to your inbox as normal.
Where to find your thresholds
Go to Aliases in the main menu and click on the alias you want to adjust. In the alias settings you’ll find the spam threshold controls where you can set both the quarantine and reject values.
How spam scores work
Every incoming message is analyzed by our spam detection engine and assigned a score. A score of 0 means completely clean. The higher the score, the more suspicious the message. Each detection rule that matches adds points to the total.
Here’s a rough guide to common score ranges:
- 0–3: Likely legitimate mail
- 3–7: Suspicious, possibly spam
- 7+: Almost certainly spam
Choosing the right threshold
The best threshold depends on how you use the alias:
Public aliases
If the alias is used on websites, forums, or sign-up forms, it will attract more spam. A lower quarantine threshold (3–5) catches more junk but may occasionally quarantine legitimate messages. This is the safer choice for high-exposure aliases.
Personal aliases
If the alias is only shared with trusted services or contacts, a higher threshold (7–10) lets more mail through with fewer false positives. You’ll rarely need to check your quarantine.
The default thresholds work well for most users. Only adjust them if you’re seeing too many false positives (legitimate mail getting quarantined) or false negatives (spam reaching your inbox).
Quarantine vs. reject
There’s an important difference between the two actions:
- Quarantined messages are held in a review queue. You can inspect them and accept any that are legitimate.
- Rejected messages are permanently blocked. You will not be able to recover them.
Keep a gap between your quarantine and reject thresholds to give yourself a review buffer. For example, if your quarantine threshold is 5, set your reject threshold to 10 or higher. That way, borderline messages get quarantined rather than lost.
Per-alias flexibility
Different aliases can have completely different thresholds. This lets you tailor filtering to each alias’s purpose:
- A shopping alias that receives lots of promotional mail might benefit from aggressive filtering.
- A work alias where every message matters might need more lenient thresholds.
Review each alias individually and adjust based on the kind of mail it receives.
Tips for better accuracy
- Use spam feedback. When you mark messages as spam or not spam, you help the system learn and improve its scoring over time.
- Whitelist trusted senders. If a specific sender’s messages keep getting quarantined, add them to your whitelist so their mail bypasses thresholds entirely.
- Check your quarantine regularly. Especially after lowering a threshold, review quarantined messages for a few days to make sure nothing important is being caught.
- Adjust gradually. Change thresholds by small increments and observe the results before making further changes.
