The following object, K1083 a damaged Hilt Plate, has been cleaned and conserved using the tools that the hoard conservators use daily to remove soil and reveal the details of the pieces.
A Meiji stereo microscope with a camera attachment was used to capture these photos and to produce this short video. These were taken at a magnification of 7.5x, to briefly demonstrate the conservation cleaning process of the Staffordshire Hoard.
The process that you will see is as follows:
1. A soft pure bristle brush is initially used to brush away loose soil sitting on the surface.
2. A small brush or cotton swab is used as a carrier for a wetting agent, a mixture of Water and Industrial Methylated Spirit (image 1). This is applied sparingly to the hard compact soil, dampening the surface, facilitating easier removal with the thorn held in a pin vice.
3. During cleaning the soft brush is used to remove loosened soil. (Image 2)
4. Techniques for using the thorn differ depending on the object, (image 3) the soil type and the amount of soil covering. A twirling, circular motion is used as well as a picking motion where the soil is lifted off the surface. The thorns are nice and pointy which enables them to get into small crevasses where soil gets trapped. They are also somewhat flexible which means that they yield slightly under pressure, allowing us to avoid undue stress being applied to the pieces.
5. A hand-held air puffer is used intermittently to blow away loose soil. In the video you will only see the very tip of the puffer.
6. Finally, a cotton swab dampened with Industrial Methylated Spirit and a stiff brush (image 4) is used to remove the final layer of soil. Multiple cotton swabs may be used, changing for a clean one each time one becomes too dirty.
7. The accession number for the object is cut out and attached to the reverse of the object using a conservation grade adhesive that will not hrm the object (HMG brand Paraloid B72 (ethyl methacrylate copolymer) from the tube), this is secured in place with the aid of a toothpick.
This video briefly demonstrates the conservation cleaning process of the damaged Hilt Plate (object K1083):
This video shows the conservation cleaning process of a sword pyramid (K551) and a silver foil fragment (K1775).
Staffordshire Hoard Conservator (English Heritage funded 3 month post)