Museums generally use B-72, a copolymer mixed with acetone, (or toluene) as a
base and protective coat for writing accession numbers on three-dimensional
artifacts. Clear nail polish can be used, as it also has an acetone base.
However, with nail polish you can't be sure about the acetone mixture or other
ingredients manufacturers may incorporate, and how they may react with
different materials.

 Black India ink is used on light colored backgrounds and white drawing ink on
dark backgrounds. Recently white colored B-72 has become available and can be
used as a base on dark objects, then marked with black India ink.
Unfortunately, white B-72 is very noticeable on the artifact, but may not be a
problem in some cases.

Numbers are applied with narrow nib pens, or Pigma pens can be used with very
light pressure (I have never been able to master the Pigma pens). Nib pens
require some practice and can be troublesome at first.  If the number ever
needs to be removed use a cotton swab and acetone.

Two-dimensional artifacts should be marked lightly with a 2H pencil in the
lower, right hand corner, of the back side, when possible. Three-dimensional
objects are marked in unobtrusive areas (where they would not be noticed when
on exhibit). Similar types of artifacts should be marked in consistent
locations when possible.

Using a very small brush, apply a coat of B-72 (large enough to write the
number on) and let it dry for at least two hours (otherwise the pen will tear
it, defeating the protective purpose). Write the number as small as possible,
legible to the naked eye. A stationary magnifying glass lamp is helpful. Dry
for two hours, then apply a second coat of B-72 to prevent the number from
rubbing off.

B-72 or nail polish should be applied in an area with good ventilation. I
usually do a large number of artifacts at the same time.

Identification tags:

All three dimensional artifacts should also be tagged with acid-free archival
tags, I use Tyvek marked with Pigma pens.  Tags should be attached with cotton
string. To facilitate handsfree inventory, the number should be written on
both sides on the tag, attached and placed where it can be seen. The less an
artifact is handled the better.  I also tag the spot where the artifact is
stored.

Metal tags, wire, paper clips, pins, safety pins, staples and tape should
never be used (although there are exceptions, such as the tagging of outdoor
agricultural implements, recently discussed on this list). All except tape
should be removed from artifacts if present. Tape removal can cause severe
damage if removed inappropriately.

Pigma pens, Tyvek, and premixed B-72 in clear and white are available from
University Products.

Hope this helps, Happy Marking!

John Gavin, Curator
Old West Museum