The drying tunnel 44 should be maintained at a temperature of from about 20??? C. to about 125??? C., preferably in the range of from about 40??? C. to about 65??? C. and most preferably in the range of from about 45??? C. to 55??? C. The drying tunnel 44 should also have a gas flow (filtered air or inert gas such as nitrogen, carbon dioxide etc. with a moisture content preferably of less than 30