I

Sodium hydrate. .....     5 parts

Soluble soda glass ...     3 parts

Flour paste.........     6 parts

Water..............     4 parts

II

Soap...............   10 parts

Potassium hydrate. ..     7 parts

Potassium silicate....    2 parts

To Remove Old Enamel

Lay the articles horizontally in a vessel containing a concentrated solution of alum and boil them. The solution should be just sufficient to cover the pieces. In 20 or 25 minutes the old enamel will fall into dust, and the article can be polished with emery. If narrow and deep vessels are used the operation will require more time.