Cleaning Copper sheets
& other metals
a basic how-to for artists and crafters
by The Whimsie Studio craftsmen

Updated Jan 23, 2023

Most metals are available in different finishes. Raw or Mill Finished metals have a brushed finish. Sculptures, Jewelry & Art pieces are almost always made of raw metal. It is then cleaned, polished or coated after it has been soldered, welded, formed or worked. The metal can also be subsequently textured, painted or patinated.
Novices often expect metals in the raw state to have a finished surface and do not consider the marring that may occur with creation of a piece; nor consider that metal cannot be soldered, braised, or welded if there is any coating on the metal. Precious metal suppliers are often vexed by expedient beginners expecting to be shipped mirror finish sheet and wire for crafting jewelry.
The only metals commonly in use that do not tarnish are fine stainless steel, pure gold and platinum. We do not offer these due to difficulty of working with stainless steel and the cost of gold and platinum. This aside, copper, brass, nickel & aluminum will last a long time with some care. Objects of these metals thousands of years old grace museums.
Copper is a very reactive metal and will gain a natural patina with time like the Statue of Liberty. With a little care copper and alloys of metal containing copper such as brass and Nickel silver can be kept bright for a long time.
First off, just as with sterling silver, keeping metal dust free, in low humidity indoors goes a long way. Avoiding harsh chemicals such as salt, salt air, bleach will keep them from corroding.Finger prints can over time even cause spots.
Second cleaning with a good gentle cleaner lasts long. Finally a coating of wax or clear lacquer can last many years. See below for details.
Cleaning Copper, Brass, Aluminum and other metals.
Copper and brass is easily cleaned using materials and products found around the house. The metal may retain an oily or greasy residue from its manufacture. This residue can be removed using dish washing detergent with a sponge or rag.
Heavy oxidation or discoloration has to be removed more aggressively using fine sand paper, abrasive pads, abrasive cleansers or chemical tarnish removers. Many cleansers (such as Bar Keeper's) contain an abrasive with a mild powdered acid which activates in water and removes oxidation. Cleansers containing bleach will remove the oxidation but the chlorine in the mix can induce a green patina. A tooth brush can be used to work the cleanser into folds or joints. DO NOT use steel wool on copper or brass as the iron in the wool will transfer to the metal and eventually cause a black discoloration. Abrasive methods of cleaning will leave a 'brushed' satin finish on the metal which can later be buffed to a polished finish.
Commercial tarnish removers and metal polishes are available for copper and brass. Follow the instructions that come with these products.
It is the nature of copper and brass to tarnish or oxidize over time. As the oxidation progresses it is referred to as 'patina' and is highly valued by some. The green patina on the Statue of Liberty is an example of this.
You can slow or inhibit the formation of oxidation using paste wax or a clear lacquer coating. There are specific brass and copper lacquers commercially available that are purported to last longer. Incralac is used by many sculptors use. One maker: CAP industries 543 Staunton St, Piqua OH 45356 They may have to be removed and reapplied if the metal tarnishes under the coating.
Paste wax or Lacquer can be applied to the cleaned bare metal once it has been thoroughly dried. If moisture is trapped under the finish coating it will tarnish. Coppersmiths in the 1800s used to pack the cleaned piece in hot saw dust to remove the moisture. Today lighting fixture and faucet manufacturers go to great lengths to prepare, clean and dry their brass fixtures for the lacquer coating that keeps them looking bright as long as possible. It is our experience that a permanent clear coating for brass and copper is very difficult if not impossible to obtain. Periodic cleaning and re-coating is always necessary.

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(c) Copyright 2009 all rights reserved -the Whimsie Studio. Larry Henke & Ronald Bodoh
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