Condition

This artefact is one from a collection that was excavated from an Anglo-Saxon burial in Scremby, Lincolnshire. The buckle is made from a copper based alloy that was actively corroding and was also covered with a thick layer of soil, obscuring the condition. In order to allow a suitable treatment to be proposed, an X-ray of the buckle was taken. This showed no damage to the body of the buckle, although it did reveal a series of crescent shaped indentations.

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Treatment Aims

To clean the artefact and stabilise the condition for storage and display.

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Treatment

The majority of the soil was removed using a stiff bristled brush as it would not scratch the copper alloy. The remaining dirt was cleaned off using a swab soaked in industrial denatured alcohol (IDA) and was allowed to dry fully before any further treatment was undertaken. It was stored in a container with a bag of colour changing silica beads in order to keep the relative humidity low and to allow the environmental conditions to be monitored.

The soft, active corrosion was removed using a cocktail stick to prevent it from catalysing the degradation of the underlying metal. When the surface was stable, the buckle was submerged in a solution of benzotriazole and placed in a vacuum chamber for five hours allowing the solution to permiate the metal and interact with the bronze disease to render it inert. Once it had dried, any excess was removed using IDA on a cotton swab. To help protect the artefact from further corrosion in the future, three layers of Incralac in toluene were painted on, and allowed to dry.