To pickle brass, heat the article in a muffle at a dark-red heat and then dip same in diluted sulphuric acid, in order to produce a clean metallic surface. After this heating and immersion, throw the article to be pickled in a tub filled with weak and impure nitric acid. This tub, or trough, is generally constructed of wood lined with lead plates, and is filled with nitric acid that may, perhaps, be best designated as second ground, as it has been used before for stronger baths. The articles when pure and of uniform color should be taken from the bath and rinsed in water, then dried in sawdust. They are next deadened. The way this is accomplished is by putting them into a nitric acid bath, diluted with about one-third water. The dipped articles acquire a coat that looks like a milky scum, which vanishes after a minute or two. Absolute uniformity is vital, and when this is obtained the articles should be immersed in strong nitric acid, this being followed up by dipping them in a number of baths of water, in order to take away all traces of acid. If the articles contain depressions which might retain acid, it must be rapidly dipped in a warm potash solution. The article when washed should be allowed to lie in clean water, to which an addition of crude pulverized tartar has been made. This method of treatment gives them the beautiful dead color on which so high a valuation is commonly placed. If it is desired to pickle the articles so they will show lustre, they should be placed at once, after being cleaned, in strong nitric acid; and should the very highest degree of lustre be desired, the entire surface should be thoroughly gone over with a scratch-brush. To polish same finely polished steel tools should be used, the articles then to be brushed over with ox-gall, and during the process be occasionally dipped in water to which a little tartar has been added. Then dry same in wood shavings in an iron pan over a heated hearth, lacquered with cold shellac solution, which can be colored by alkanet, dragon's blood, etc.