This is adapted to treating silver filagree ornaments, rendering them dead white. The process has long been a trade secret. If any pewter is found in the articles, it should not be attempted. Pound together charcoal 3 parts, and of nitre 1; add sufficient water to form a paste. With a camel's-hair brush give the article a thin coat of the mixture, put it in a small annealing-pan, and submit it to the fire until it becomes red-hot; then withdraw it from the fire, let it stand a minute, and turn it out into a weak solution of sulphuric acid (1 part acid, 10 parts water) in the boiling-pan. Boil, pour off the acid, rinse; wash with warm water and soap, using a soft brush; dip in spirits of wine, and dry in boxwood sawdust. If any spots should still remain on the work, anneal it without the mixture, boil out and wash as before. Burnish the parts intended to be bright. Do not use the common American saltpetre. The English nitre, although it costs more, is really less expensive, as a smaller quantity goes further and does the work more effectually. Purchase at the wholesale druggists.