Re: collection after fire

[| <libsdnhm@xxxxxxxxx>]

Re Dr. Hilbrecht's comments on dust and soot on fossil specimens: dust 
can be surprisingly damaging over time, particularly if it is abrasive or 
acidic (increasingly common, sad to say). When the specimen has been 
treated or coated with a thermoplastic polymer, and the temperature 
fluctuates., dust on the surface sinks into the coating and becomes 
inextricably part of it, resulting in an increasingly dirty surface that 
can seriously impair the analysis of key characteristics (and be a real 
nightmare to remove). Old shellac and old beeswax are especially prone to 
hold dust and dirt over time and are sometimes very difficult to remove 
without damaging the specimen. One major project related to this that 
comes to mind was the cleaning of the fossils in the proboscidean hall at 
the University of Nebraska. Soot is a somewhat different problem because of 
the fineness of the particles and, of course, the potential for carbon-
black staining. 

Sally Shelton
Director, Collections Care and Conservation
San Diego Natural History Museum