Gmail's Spam filter generates an unacceptable number of false positives for me, and I'm very wary of losing real emails. I don't really want Gmail to delete anything by default, as I don't necessarily remember to check the Spam folder every month.

So, I set up a filter on the search "is:spam" and set it to:

  • Skip the Inbox
  • Apply the label: spambin
  • Never send it to Spam

This works as intended, and now suspected spam goes into my, spambin folder instead of the Spam folder, and isn't auto-deleted.

However, Gmail still puts a lot of real emails into the spambin folder, so I'd like to train it to work better. But because the emails are no longer in the Spam folder, there's no Not Spam button for me to press, even though there's still a warning that Gmail thought the email was spam!

So my questions are:

  1. If I add the non-spam back into the spam folder and then press the Not Spam button, will this have the desired, training effect?

  2. Or will the action of putting it in the Spam folder make Gmail extra sure that the email is spam, and then pressing the Not Spam button just negate this action?

  3. Or is creating the filter equivalent to pressing the Not Spam button for every email, and so I shouldn't need to train Gmail further? (This doesn't seem to be the case, so far.)

  • 2
    gmail spam filter works fine with me. Very few ( almost none in past 12 months) false positives. Not sure what's wrong with you.
    – Graviton
    Jul 28, 2010 at 12:44
  • About 10-25% of the emails Gmail marks as Spam for me are false positives. :(
    – Rich
    Aug 27, 2010 at 10:57
  • I have got a whole LOT of false positives when initially importing about a thousand messages from my totally "clean" external POP3 mailbox. I was quite amazed with that, actually. Oct 11, 2013 at 18:01

1 Answer 1


By bypassing the spam filter with creating your own label, you are taking away Gmail's learning capabilities. There is probably a reason your emails are getting filtered as spam (lots of images, certain keywords, etc.)

I would suggest going back to the default: taking off your custom spam filter, placing all the known spam into the spam box by hitting the "Report Spam" button, and keeping an eye on the spam box for a while.

  • Okay, thanks for the suggestion. Just to clarify, your answers to my specific questions are "no", "no", and "no"? What happens if I move an email into my Spam folder and then click "Not Spam". Nothing at all?
    – Rich
    Jul 28, 2010 at 17:02
  • In theory: 1. yes, 2. no, 3. no. If you moved it into the spam folder, and then clicked "Not Spam" it should only use the last action (in this case mark it not spam) as part of its training. But note: by moving something that isn't spam into the spam folder and then back out you're just creating more work for yourself though (since it already knows its not spam.) Jul 28, 2010 at 20:55
  • Creating a small amount of work for myself is acceptable if it means I can improve the Spam recognition whilst still ensuring there is 0% chance that a non-Spam email is deleted automatically before I see it. Thanks for the info! One question though: are you basing this on knowledge/documentation of Gmail's code, or on comparison with other spam filters? Because I know at least one Bayesian spam filter that works differently to how you describe.
    – Rich
    Jul 29, 2010 at 10:25
  • Just based off of previous 6 years of working with Gmail. Jul 29, 2010 at 15:12

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