I really thought the list would be inundated with references on this one,
particularly from academia and conservators.  Since it hasn't been, I'll add
the ones used when I took a conservation course in the dark ages as well as
a couple I've picked up since.  Assuming that the search is for conservation
guides (as opposed to artifact identification), try these:

Sease, Catherine
  1992  A Conservation Manual for the Field Archaeologist.  Institute of
Archaeology, University of California, Los Angeles.

[Note:  the same group puts out a manual on archaeological illustration and
one on photographing artifacts--all reasonably priced.]

Hodges, Henry
  1976  Artifacts:  An introduction to early materials and technology.  John
Baker, Bedford Row, London.

Plenderleith, H. J. and A. E. A. Werner
  1976  The Conservation of Antiquities and Works of Art:  Treatment, Repair
and Restoration.  Oxford University Press, London.

Of course, the Hodges and Plenderleith may be out of print now.  Noel Hume's
Historical Archaeology also has some information on artifact processing and
conservation.  In addition the University of Florida Anthropology Dept.
published a student-produced lab manual in the early 1980's--copies may
still be available through the dept.

                                Happy Hunting--Lucy Wayne