To Remove Stains From Enamel Dials
American Watchmaker and Jeweler (1892)
Important: Safety Warning
This page describes trade processes that use dangerously toxic materials such as cyanide solutions, mercury amalgams, or strong acids. These processes require training, equipment, and precautions far beyond what the text describes.
This information has been left in for historical purposes but should not be acted upon.
Enamel dials sometimes have black or cloudy stains upon their faces, caused usually by the tin boxes in which they are shipped. These can be removed with a piece of soft tissue paper previously dampened with nitric acid. Wipe the stained places, carefully avoiding the painted portions as much as possible, for in some very cheap dials the painting is not well fired, and may be injured by the acid. Wash the dial thoroughly in clean water and dry in sawdust. To Reduce the Diameter of a Dial. Rest the dial in an inclined position and file the edge with a half smooth file, dipping the file in turpentine occasionally, and finish with a fine emery stick. To Repair a Chipped Dial. Gently heat the surface of the dial and fill the hole with a compound of white lead and white resin, heated over the flame of a spirit lamp. It is better to heat the blade of a knife rather than the wax, and run no risk of discoloring the wax. Cut off a small piece of the wax and run no risk of discoloring the wax. Cut off a small piece of the wax and press firmly into the hole, allowing it to project a little above the dial. When cold, scrape down even with the dial, and finish, by holding it close to the flame, when the patch will gloss over nicely. Be careful and do not get it too close to the flame, or you may turn the enamel yellow. A mixture of white lead and white wax applied and polished by friction is also used, but it is not as handy and is not as capable of a high polish.
What Has Changed in the Last Century
When the American Watchmaker and Jeweler printed these recipes in 1892, an enamel dial was a working part to be filed down, patched with white lead and resin, and scrubbed with nitric acid on tissue paper. Today the same dials are collectors' items, and the guiding principle of horological restoration is the opposite: an original dial with honest stains is worth far more than one that has been acid-cleaned, refinished or reduced in diameter, and visible repairs are expected to be declared when a watch is sold. Specialist restorers now fill chips with tinted epoxy or fired glass enamel rather than lead-based wax, and cleaning is done with mild detergents, ultrasonic baths or dilute hydrogen peroxide instead of strong acid. White lead itself has been progressively banned from ordinary use in paints and pastes across Europe and North America through the twentieth century, and the tin shipping boxes blamed for the staining have long since vanished from the trade.
Written for this edition, 2026.