CLEANING DISHES Dishes used for " hypo " should not be put to other photographic purposes, even after clean ing, as any print treated therein is liable to be stained. Dishes used for developing and toning soon become dirty, particularly when the de veloper oxidises quickly, as pyro, for example. All dishes require to be cleaned at intervals, but those made of porcelain appear to require the most cleaning. There are two kinds of stains, those which appear on the surface of the glaze, and those which find their way under the glaze into the very substance of the dish, from which it is almost impossible to remove them. A solution of hydrochloric acid will remove most surface stains without damaging the dish, the method being to pour water into the dish and add hydrochloric acid until the solution is strong enough ; commercial spirit of salt will do equally well and is cheaper. An old tooth-brush, or
a rag tied to a stick, may be used for the corners, it not being advisable to use the fingers. Fresh stains will not require to be rubbed. For obsti nate stains, mix together 8 oz. of pearl-ash, 4oz. of quicklime, and i pint of water, stir up and place in the stained dishes ; allow to remain for one hour, pour out, rinse with very dilute hydro chloric acid in order to destroy the last traces of the pearl-ash and lime, and finally wash well. However, spirit of salt is more generally used, and it makes dishes chemically clean enough, even if it does not entirely eliminate the stains.
To remove slight stains from fragile dishes, rub damp salt on them with a piece of flannel, or rinse with very dilute hydrochloric acid and then rub with salt.