I understand Tom's concerns, because it is a massive problem for us as well.
For the past few years, we have been using what we call a "Decisions" notebook
(actually several 3-ring binders), into which we put photocopies of the covers
of items that we do not wish to keep.  When one of the checkers comes across
something that is not in the system, he/she has a search strategies list that
includes among its choices looking in those noebooks.  It is a cumbersome
system, and one that we would love automate, but it it too soon to put it on
NOTIS.  Once bib records can be suppressed in the new release, we may very well
enter "dummy" records in the system, thus eliminating this manual file.  In Bill
   Drew's situation, it sounds as though the number of freebies he receives may
be small enough for him to personally intervene (he used the word "clerk", not
"clerks").  In my case, 8 clerks on 2 campuses would be funneling anything
they did not recognize to my attention, and I not only do not have the time to
review those items, I really don't want to see them.  The actual decisions are
made by our collection management librarians, and the titles are usually either
discarded on receipt or added to the collection for limited retention (6-12
months).  If anyone else has a more efficient system developed, I would love to
hear about it.

Steve Murden
Virginia Commonwealth University