>
> I have always seen sherds, points, etc. marked with white or black
> (depending on your surface) drawing ink or India ink, using a
> dipping pen. The number, once dried, is then covered with a thin
> layer of clear nail polish.  This has the benefit of being removable.

Eeeeek! Not the nail polish!  I worked in the Anthropolgy section
of the museum here for one semester, and the collection's
assistants were always griping about trying to break the campus
anthro department of the nail polish habit.  I'm not real up
on the technicalities, but basically, nail polish has lots of extra
nasty things in it that really arent good for objects.  I _believe_
(dont flame me if i get this mixed up :) ) that our museum's anthro
department uses PVA in acetone for this purpose.  Its the same basic
ingredients without all the nasties that are in nail polish.
Oh, and one more thing, put a layer of this mixture under the number
as well as on top of it, this lets the number be removed or changed
much more easily.  Reversibility, reversibility, reversibility :)

Vanda Bushfield
Grad Student
Texas Tech University