Pickling
Mild surface fire stain can be removed during pickling. Even a stubborn fire stain can often be removed by repeatedly pickling. However, if 3 or 4 attempts are not successful, then a more aggressive process will be required.
Abrasion
A sure way to remove fire strain is to physically remove the metal using emery paper or a file. Monitor progress carefully, as removing too much material can result in spoiling the shape or details of the article.
Depletion gilding
This process involves repeatedly heating and pickling a sterling silver article. The torch flame oxidises the copper on surface of the work piece. The pickling process will then remove this copper oxide. After a few repetitions, the surface of the article will be covered in a thin layer of fine silver. As this layer is very thin, the surface should be pre-polished prior to depletion gilding. A final polish can be applied with a light application of rouge, a barrel polisher or a burnisher after the depletion gilding process. Alternatively, carefully use a soapy brass brush between each heating to achieve a satin finish.
Scratch brush
Fire stain is most evident on a smooth, highly polished mirror finish. The visibility of firestain can therefore be hidden with a different surface finish. Brass brushes or glass fibre scratch brushes can be used to create a satin finish to the article that will obscure much of the firestain.
Texture
Using hammers, punches or chasing tools to create an interesting surface treatment is one of the best ways to hide serious firestain. Not only does the broken play of light across a textured surface help to hide fire stain, it also makes an item of jewellery look individual. This sets it apart from the mass produced majority of modern jewellery.
Electroplating
If you must achieve a uniform mirror polish, sending the article to a commercial plating company can prove to be effective. On areas subject to a lot of wear, this thin layer will rub off over time.
