Conservation of Lead Coins

     Lead is one of the ancient metals. The Romans used lead for lead water pipes. The use of lead is found in coins also. The Pallavas, the Satavahanas, the Pandhyas and the Cholas used lead in the minting of coins. As lead is very soft and easily degradable material, the lead coins need to be attended very frequently as they disintegrate very fast and converted into powdery materials. The same thing happens in the case of lead coins from Andipatti in Tamil Nadu. The coins are fairly in good condition excepting few of them. The affected coins were treated with Amberlite IR 120, an ion-exchange resin to remove the corroded matter. In the case of lead coins, they were kept covered in a warm solution of distilled water with Amberlite IR 120. The corroded lead portions are cleaned by ion-exchange method and the corroded salts are cleaned and the metal is conserved. Unprotected lead will be corroded further, if the bare surface is exposed to the atmosphere. Therefore, the coin is impregnated under vacuum with the help of 2% solution of poly vinyl acetate in acetone.

Before Treatment

Conservation of Ceramics    

     Ceramic is fired clay. There are many types of firing of clay materials. One is open firing and the other is inverted firing. Normally fired clay will appear red and black. Unless the potteries are glazed they cannot be used to keep liquids. Therefore glazing is done after white clay vessels are fired by coating a paste containing the mineral colouring material. This practice was in vogue during the Moghul rule in India. The East India Company in India too prepared ceramic vessels.

     The broken ceramic plate is cleaned with rectified spirit and teepol to remove the oily accretions and the edges were cleaned similarly to provide effective adherence. The broken edges are mended with quickfix, an adhesive, which sets quickly. The broken and lost portions are reconstructed with the help of white M-seal. A support is provided to reach the proper positioning of the mended portions. If the portion has any painted details, the painting is done with acrylic colours.

After Treatment

Before Treatment

Conservation of Silver Objects / Coins

     Silver is a noble metal, which turns black (silver sulphide) and white (silver chloride). The blackening of silver is called 'tarnishing'.

     Silver objects / coins are cleaned by keeping them in a 10% solution of formic acid to remove the black colour (silver sulphide) and immersed in a solution of 10% ammonia to remove the white colour (silver chloride). After thorough washing, the coins are dried and coated with a 2% solution of poly vinyl acetate in acetone as a preservative coating.

After Treatment