To make Letters or Flowers of Blue on Polished Steel.

The Scientific American 35, 22.5.1847

Hold the steel over a charcoal fire till it becomes blue — let it cool. Then with equal parts of rosin and beeswax, melted together, colored a little with lampblack, and diluted with spirits of turpentine so as to work freely with with a camel noir pencil—draw any letters or figures on the steel while it is a little warm. — When the steel has become cold, wash it over with muriatic acid, diluted with two parts of water, to one of acid; thus take off the blue color, and then wash it with clear water. Afterward the varnish, being warmed a little, may be readily washed off with spirits of turpentine, and the letters or flowers will remain blue. If letters are formed on polished steel with this varnish, and the body of the metal be all covered with it, excepts a small space round each letter, and then bathed with muriatic acid, the space round the letters will become a dull iron color, while the letters and body of the steel will retain their polished surface and brilliancy.