Gold, platinum and precious stones are not exposed to weather conditions. Remove dust and grease from their surfaces by scrubbing with a soft brush, damp with a solution of soap or any synthetic detergent. Partly lost, as a result of a clash, shine can be restored with polishing mixtures, it is often enough to polish with a clean piece of cloth. Silver turns black after some time due to the action of hydrogen sulfide, found in minute amounts in the air. They should be cleaned with polishing mixtures, containing ammonia water. In the absence of other measures, you can use any toothpaste with a little ammonia water added.
Imitation jewelery is usually made of aluminum alloys. It owes its golden color to the exterior, quite permanent, alumina layer. This layer is very hard, but very thin at the same time (a thickness of several thousandths of a millimeter), it can therefore be damaged or worn when rubbed with hard substances. Do not use cleaning agents containing alumina, chromic oxide and ferric oxide. Usually a soft brush and a soap solution are sufficient.
Decorative metals are usually coated with a thin layer of colored chemicals. Be careful when cleaning them, so as not to rub off this colored coating, which can occur both as a result of mechanical abrasion, as well as the chemical action of cleaning agents. Mixtures containing ammonia water must not be used to clean patinated copper and its alloys, because it dissolves most of the copper compounds, forming a colored coating. Also, some synthetic detergents may be similar. So the safest cleaning agent is a water-based soap solution. After drying, the surface of the items should be gently rubbed with oil for better preservation. The coating can be renewed in worn areas.