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Byzantine lead seal; circular; impressed with (now incomplete) cruciform monogram on one side, four-line Greek inscription on the other.
- Diameter: 25 millimetres (max)
Inscription Positionobverse angles
Not on display
17 November 1999
Reason for treatment
Active lead corrosion spots. Stabilize active areas.
The surface has a concretion-like appearence. Conversion of the lead into corrosion products seems to be very deep, mix of blue, orange, white and greyish colours.
Soaked in acetone. Stabilized by local electrolytic reduction using a 5% aqueous sodium hydroxide electrolyte on cotton wool swabs with a graphite anode, for 1h55 hours. Rinsed in gently running tap water for 2 hours. Stabilized by consolidative electrolytic reduction in a 5% aqueous solution of sodium carbonate electrolyte using stainless steel anodes, for 124 hours (20 to 30 mA). Manual cleaning using a scalpel. Deposit from reduction removed by brushing in running tap water with a stiff hog hair brush. The reduced lead was rinsed in tap water for 18 hours then neutralised in dilute sulphuric acid and finally washed in gently running tap water for 6h45 hours, and then soaked in THREE 20 minutes distilled water bath. It was dried through Industrial methylated spirits (ethanol, methanol)/acetone solution and then acetone alone. Consolidated by immersion in Paraloid PB72 5% in acetone, and a coating of Paraloid PB72 10% in acetone applied with sable brush.
Britain, Europe and Prehistory
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Object reference number: MCB2804
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