[exim] is this spam unable to track source

Hi

In my crontab I have tidyup commands and in the last few days I am seeing a
few dozen of these every day all to yahoo.


T:mx3.mail.yahoo.com:64.156.215.6:1F0ORk-000LHA-QR (no message) deleted T:
mx3.mail.yahoo.com:64.156.215.5:1F0ORk-000LHA-QR (no message) deleted T:
mx3.mail.yahoo.com:64.156.215.18:1F0USw-000CmK-QD (no message) deleted T:
mx2.mail.yahoo.com:4.79.181.135:1F0T4V-0000cP-L2 (no message) deleted T:
mx3.mail.yahoo.com:64.156.215.8:1F0QTt-000Mjm-2p (no message) deleted T:
mx2.mail.yahoo.com:67.28.113.19:1F0T4V-0000cP-L2 (no message) deleted

yet when I run exim -bp there isnt anything related to yahoo listed, so
where is it finding these stale yahoo emails? Or am I looking in totally
the wrong place?

Need some help here as I am trying to diagnose if my server is been used to
send spam to yahoo or if its something else, I am seeing a few emails from
yahoo been blocked by my anti virus in the rejectlog but nothing concerning
outgoing emails.

Chris