Jars for biological specimens

We have an extensive collection of wet specimens in ethanol solution
in 'historic' glass jars with ground glass stoppers. Many of the
stoppers do not seal well so we can have significant evaporation of
solution. Over the years various materials have been used to prevent
evaporation including silicone sealer and petroleum jelly. Both have
proved less than effective, with silicone not stopping evaporation
and petroleum jelly sliding down into the jars and onto specimens.

We are not able to transfer the specimens into newer, better sealing
jars; so we are now in the process of removing silicone sealer and
replacing the ethanol solution. In order to reduce evaporation, we
have been tying Parafilm M film over the jars and stoppers.
Recently, after a record heatwave, we have noticed splitting of the
Parafilm in areas of mechanical stress (where stretched over hard
edges).  We feel that the roll of Parafilm we were using may have
been heat affected and it finally failed in the extreme heat.

We are investigating replacing the Parafilm with DuraSeal lab film
as it has better heat resistance, but it has suggested that we
resume using petroleum jelly. I am reluctant to use it considering
previous experience.

Could anyone with similar experiences suggest any other methods of
reducing evaporation? Another major consideration is that we would
have a limited budget and staff time to work on this collection.

Alayne Alvis
Conservator
Sydney University Museums
Rm H102, Main Quad A14
The University of Sydney NSW  2006
+61 2 9351 2761
Fax: +61 2 9351 2881


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                  Conservation DistList Instance 24:38
                 Distributed: Sunday, February 13, 2011
                       Message Id: cdl-24-38-023
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