[NHCOLL-L:4177] Removing nicotine stains from minerals

[Gregory Brown]

The following query found its way to the Vertebrate Paleontology
Preparation discussion list.  There is likely more expertise monitoring
NHCOLL-L than our prep list, so I've crossposted the query here.
Thanks, everyone, for you comments...I'll make sure they are forwarded
to the VP preplist.

Gregory Brown
Chief Preparator Vertebrate Paleontology
University of Nebraska State Museum
402.472.2657
GBROWN1 at UNL.EDU

Forwarded query:

"We've just been given a rather nice mineral collection. Previously, the
specimens had spent several decades on open display shelving, in a
cigarette-smoke rich atmosphere. Many of the specimens have a dull
yellowish nicotine/smoke/dust tinge, which impairs the natural
colour/lustre, and reduces their visual appeal.

Is there a particular recommended way of removing this, and restoring
the original lustre of the specimens? Obviously there is a wide range of
minerals species with different chemical properties, so particular
treatments may not be appropriate for everything. However, any
suggestions gratefully recieved, especially if they can be performed
safely in an open sink or similar. If necessary, fume-cupboard
approaches might also be feasible though."