If you create spambox@mydomain.com (replace mydomain.com with your real domain name), all SPAM sent to @mydomain.com will reach spambox@mydomain.com.
Now if you login on your pop3 account spambox@mydomain.com, you can see all the spam which reached your domain name @mydomain.com. If you see a false positive (good email), you can forward (or forward as attachment, better) the email to the destination contact, for example your-staff@mydomain.com.
You can check spambox@mydomain.com such as any other email account on your server using your email client; or webmail Horde, Squirrel or Roundcube.
