Metals - Properties and Cleaning

For antiques and for anything valuable or old seek expert advice before doing anything other than washing with mild soap and water. Exercise good judgment. It is usually better to retain the natural patina. Do not act in ignorance – research first. This is intended as a quick guide only.

Element: Substance (on this page metal) that cannot be split chemically into simpler substances.

Alloy: Mixture of metals.

Electro-plating: covering one metal with a plating of another (e.g. copper bowl plated with silver). For further information see finishing.com:

http://www.finishing.com/faqs/howworks.html

Metal	Symbol	Properties	Alloys	Oxidation	Cleaning
Platinum	Pt	The precious metal. Primary use jewelry, also electronics. Introduced to Europe by the Spanish in 17th Century,		Negligible	Jewelers Cloth
Gold	Au	Soft malleable metal. This precious metal is / was used for coinage, false teeth, decorative art and jewelry. Also used in electrical components.		Negligible	Jewelers Cloth
Silver	Ag	Soft malleable metal. This precious metal is / was used for coinage, cutlery (flatware), candlesticks, serving utensils, decorative art and jewelry.	Includes, Cadmium (historical), nickel (historical coinage).	Silver darkens (e.g. old tea set). Will happen over time in air, expedited by contact with Sulfur and Chlorine. Storing silver in brown paper accelerates oxidation.	Silver Polishing Cloth Silver Cleaner Soft Brush and elbow grease for stubborn areas of darkening.
Aluminum	Al	Very light metal, many uses from kitchenware to automotive and aerospace industries.	Alloyed with Zinc, Copper, Magnesium, Silicon	Slow to oxidize.
Antimony	Si	Used to harden (modern) lead free pewter.
Copper	Cu	Properties: High Electrical and thermal conductivity. Non magnetic Used for: Just about everything. Examples: electrical; plumbing; and, kitchenware. http://www.copper.org/	Brass Bronze	Copper is very slow to oxidize. It will eventually develop a light green patina.	Copper / brass polish. Patina may easily be stripped (paste, 4 parts salt to one part lemon juice). Unlikely to be required.
Lead	Pb	Soft malleable metal. Low melting point. Had / has many applications: Water piping / heating systems, toys and paints.	Pewter (Historic)	Lead is very slow to oxidize.	Avoid – this metal is toxic.
Nickel	Ni	Coins made from this metal were made since ancient times minted (235 BC in China. Nickel is also used in electrical products.		Slow to oxidize.
Mercury	Hg	Mercury is a liquid heavy metal. It is commonly used in thermometers and barometers. Also conducts electricity (e.g. trip switch).			Toxic Dangerous
Tin	Si	Known since ancient times. It is very soft and the major component of Pewter (90 – 98%). Copper, Antinomy and Lead used to harden.	Pewter	Slow to Oxidize.	Metal polish with a soft cloth can be used (silver or brass).
Zinc	Zn	Since ancient times, zinc has been alloyed with copper. Not often encountered in pure form.	Alloyed with Aluminum