When a museum accepts an object into its collection, that institution has made a promise to take care of that piece of history, forever. Because most pieces of cultural heritage are not created to last forever, the museum takes certain steps to extend the life of an object. This includes special care in the areas of cleaning, and for metal objects, polishing.
Polishing vs. Cleaning
The silver in the Montpelier Collection is largely from the 1800s, having been through years of service, storage, and display. Those years of use give each piece its own history and perhaps visual evidence of the use- a scratch, dent or missing element. When caring for an object, our goal is not to make it look perfect, rather to maintain its stability. Cleaning the silver- removing dust from its surface- takes place regularly throughout the year, whereas polishing- removing tarnish build up- is done annually, to reduce the chance of damage. In fact, every time a silver object is polished, some of the underlying silver is removed alongside the tarnish. If the silver in the collection were polished multiple times a year, the piece would be all but gone! Tarnish build-up is inevitable when silver is exposed to various compounds in the air, which means all of the silver on display in the House will accumulate tarnish build up over time. Knowing this, we work hard to strike a balance and therefore take care to remove dirt and dust, gently polishing the silver as to not over clean, potentially damaging the collection piece.[1]
Let’s Begin!
But first, remove your jewelry, please.
When working with collection objects it is important that YOU are not being a hazard to the piece! Rings, watches, dangling necklaces, neckties, and earrings should be removed for both the technician’s safety and the safety of the object. These things can become caught, entangled, or scratch the surface being worked on. Objects, especially metals, are severely susceptible to damage from the oils on a human hand. Therefore, hands must be covered with either cotton or nitrile gloves. Once all accessories are removed, a pair of gloves and a lab coat are put on, we’re ready to go!
To begin, a stability assessment is taken to ensure the object is secure and able to withstand handling, brushing, and eventually polishing. Dirt and dust are removed from the surface with an artifact dusting brush. The brush has natural animal hair bristles to avoid any scratches that would occur with a synthetic brush. The dusty object is gently brushed, noting any areas of damage or structural instability. A metal object can consist of multiple parts attached together that, with age, have become less secure. It is important to understand the construction of the object before handling, so it can be well supported.[2]
The Secret Formula
Once the dust is removed, we’re ready to polish. At Montpelier, we make our own silver polish in-house. In order to remove tarnish from the surface of a silver object, the polish or cleaner used must contain some sort of abrasive. This abrasive is what creates enough friction to remove the tarnish, but it can also leave behind surface scratching. [3] However, different methods employ different abrasives, which means a range of how much silver is removed and how much scratching is left behind. Commercial products contain harsh chemicals that are among the most abrasive and often do more damage than good in the long run, [4]
And we want to keep this silver for the long run.
The silver polish we make consists of calcium carbonate and distilled water, mixed together to form a paste. We choose this method because creating a mixture of calcium carbonate is among the least abrasive methods of cleaning silver. When suspended in water, calcium carbonate is adequate at removing tarnish but removes very small amounts of silver and scratches the surface significantly less than other methods.[5] The paste is then evenly applied to the object’s surface with a clean cotton cloth. The paste dries quickly to a powder, and then, with a second cloth, is buffed off, revealing the illustrious silver underneath.
Silver, like this water pitcher seen above, can have intricate design elements that trap the calcium carbonate paste, making it difficult to remove with just a cloth. For these sections, a clean cotton swab or bamboo skewer can be used to remove the dried paste. Use of the skewer is reserved only for when absolutely necessary as the strong surface can scratch the silver more easily than the cotton swab. . After as much of the paste is removed as possible, there may still be residue, particularly in those difficult to reach areas. To remove all calcium residue, a clean cotton cloth is dipped in a small amount of denatured alcohol and the silver’s surface is wiped down.
Now the silver is ready to shine! These pieces, generously on loan to Montpelier from the New York Historical Society, along with other silver in the Montpelier Collection, will receive this special treatment once a year with routine dustings in between.
Works Cited
[1]“Cleaning Metals: Basic Guidelines.” Cleaning Metals: Basic Guidelines, Victoria and Albert Museum, Cromwell Road, South Kensington, London SW7 2RL. Telephone +44 (0)20 7942 2000. Email Vanda@Vam.ac.uk, 12 Nov. 2015, http://www.vam.ac.uk/content/articles/c/cleaning-metals-basic-guidelines/.
[2] ibid
[3]“Silver – Care and Tarnish Removal .” Canada.ca, Government of Canada, 22 Feb. 2019, http://www.canada.ca/en/conservation-institute/services/conservation-preservation-publications/canadian-conservation-institute-notes/care-silver.html.
[4] ibid
[5]Wharton, Glenn, et al. “A Comparative Study of Silver Cleaning Abrasives.” JAIC Online, Journal of the American Institution for Conservation , 1990, cool.culturalheritage.org/jaic/articles/jaic29-01-002.html
