Dear Charlie;-
    Most collectors and displayers don't do shells in a museum sense. They (we) put out our pretty shells so people who come to visit will say" Aint them purty!!"
   What we do to  make them look purty is shine-em-up. We use mineral oil, glycerin, spit, and etc. to make 'em look purty. Look at it this way: If shells were ugly---who'd collect or be interested. How many people do you know who take pride in their collection of banana slugs?
      Art

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---- Charles F Sturm <[log in to unmask]> wrote:
> Matt and Conch-l'ers,
>
> I agree with the general techniques that folks have been writing about
> regarding using mineral oil or silicon oil for adding gloss back to a dull
> shell. I agree with avoiding animal and vegetable based oils as they
> become rancid over time. However, I would like to ask the question
> differently, "Why oil shells?" Why do we need to have every shell appear
> glossy? I would argue that in doing this we are losing information and
> possibly contaminating specimens.
>
> I collect fossil mollusks for the most part and I never add a surface
> protectant to them. I will soak some of them in a consolidant (Butvar 76
> in acetone) if they are very friable. I note such treatment on the labels
> accompanying these specimens.
>
> I rarely collect live material; most of my self-collected Recent shells
> are freshly dead or specimens that have been banging around for a while in
> the surf. To me the dullness of the shells is an indicator of postmortem
> changes. This is information that I do not want to lose. Also, if someone
> would ever want to use one of these specimens for destructive testing
> (i.e. chemical analysis) a treatment with oil might very well make such an
> analysis meaningless. At the Carnegie Museum, we occasionally receive a
> request for a specimen that may be 50-100 years old so that such analyses
> can be done and compared to the chemical composition of Recent shells.
>
> Some will say that you have to prep the shells to preserve the
> periostracum (for instance in Unionoida). This can also be accomplished by
> carefully controlling the temperature and relative humidity of the space
> where one stores a collection.
>
> So in the end I pose the question, "Can we only appreciate shells if they
> are glossy, or can we save time and leave them as they came from their
> environment?" One possible alternative that may satisfy both camps is to
> treat some (maybe for a display) and store a few others (untreated) for
> posterity in a zip-lock bag.
>
> While this question is rhetorical and posed to have us think about
> alternatives to how we do things, I would also be interested in reading
> others thoughts on this subject.
>
> Regards,
> Charlie
> ******************************************************************************
> Charlie Sturm, Jr
> Research Associate - Section of Mollusks
>                       Carnegie Museum of Natural History
>                      Pittsburgh, PA, USA
>
> Assistant Professor - Family Medicine
>
> [log in to unmask]
>
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