AbstractSeveral methods have been proposed for the detection of washed eggs. It is known that washing reduces the amount of potassium chloride on the shell and increases the electrical resistance of a drop of water subsequently placed on the shell. The method based on resistance has been examined in detail, and a search has been made for new methods. It was found that washing also tends to deplete the surface of the shell of magnesium, but the most promising method was based on the photochemical reduction of silver chloride on a test paper exposed to ultra‐violet light. A sensitive and semi‐quantitative form of chloride test is descri