On Sunday, Tongariki asked:

>I am seeking information on oleates of copper and mold bloom on leather
>artifacts.  I need to know how to stop these pests and what the
>recommended treatments are so that I can have an informed and intelligent
>conversation about a conservator.  Also this will help me separate those
>in need of immediate intervention from those needing simple stabilization.
>Your thoughts please?

Oleates on copper, often known as verdigris, is a result of a chemical
reaction between copper and natural oils or fatty acids. it usually results
in a waxy, green deposit. You will often find "verdigris" on copper that is
in contact with leather - the natural oils and/or leather dressing (yuk!)
in the leather is the culprit. It can usually be removed quite easily with
acetone, ethanol or industrial methylated spirits (IMS). Once removed you
may notice that the copper underneath is bright and untarnished in
comparison with non affected areas.

The mold bloom may also be a result of too much leather dressing. It may
not even be mold but just excess dressing precipitating on the surface.
This is one of the reasons why we don't use, or recommend the use of,
leather dressing at the Australian War Memorial.

George Bailey
Objects Conservator
Australian War Memorial
Treloar Centre for Conservation
4 Callan St, Mitchell, A.C.T. 2911
Australia
Phone: +61 6 241 6122
fax:   +61 6 241 7998
email: [log in to unmask]