Conservation of Artifacts 

Background: Conservation of artifacts has two phases: 1) preventive conservation, including cleaning and repair of artifacts and environmental controls in display and storage spaces, and 2) conservation intervention, which is more treatment oriented and can be expensive.  No conservation intervention work is currently being done. 

Many of the artifacts in the collection may be worthless in twenty years without some form of conservation.  Once an object deteriorates or is damaged, it can never be fully restored, even through costly conservation treatment.  If conservation work is done on an object that was deteriorating because of a poor environment, it is a waste of money to treat the object and then return it to the same environment.  Most of the collection, however, will continue to be stored in less-than-ideal conditions in either Virginia City or Nevada City.  

Most of the Virginia City and Nevada City collection is displayed seasonally in furnished building displays (the artifacts are left in place in the buildings during the off season, generally with the windows covered to prevent light from entering).  Because most of these spaces are environmentally uncontrolled - the buildings are not sealed - the condition of the artifacts has deteriorated over time.  Many of the building displays have not been changed at all for over twenty years; some have been in place for over fifty years.  The artifacts in the displays may look intact to the public, but when they are touched, they simply disintegrate.  To the Boveys, an item soiled by the dirt and wear of use was more “valuable” than a similar new, unused item.  This approach cannot be continued, however, without irreversible damage to the artifacts.  

Sunlight, temperature, relative humidity, and biological agents are the most serious threats to the collection.  Some displays are infested with pests such as dermestids.  Many fragile items susceptible to damage by light are located in store display windows.  These include boxes, labels, fabric, anything printed or painted, and wood cabinetry.  The bread, candy, and other food items on display in several buildings is real food, some of it twenty years old, posing a health risk from mold, fungi, and vermin.  Some cans on display are leaking, some have exploded, and labels have popped off bottles.  Visitors drop food in buildings and climb on vehicles stored in outbuildings.  

Southwestern Montana is a region of low humidity, and this has undoubtedly helped preserve the artifacts over the years.  According to one expert, the player pianos in Nevada City are better preserved than almost any others in the country; several are still operating with the original rubber tubing.  Even so, low relative humidity can cause desiccation and embrittlement or splitting of many materials.  High relative humidity, on the other hand, promotes corrosion of metal (such as the metal on stoves or harnesses), the growth of mold and fungus, and insect activity.  Relative humidity should ideally be maintained at a stable point between 40 percent and 65 percent, with fluctuations no greater than 3 percent in one day, with gradual seasonal variations.  Extreme fluctuations of both temperature and humidity in one day can be very damaging to artifacts.  Pronounced fluctuations cause structural damage such as cracking of wood and detachment of component parts.    

Sunlight and some artificial light acts cumulatively to promote the breakdown of molecular bonds in materials, leading to embrittlement and the fading and darkening of pigments and dyes.  Light can damage wood, textiles, paper, leather, paintings, photographs, natural history specimens, and other organic materials.  These effects can be minimized by limiting exposure time, lowering the light levels, and filtering out the visible light.  Interior lighting systems should be low in ultraviolet emissions.  Incandescent lighting should be used in collection areas instead of fluorescent bulbs or lamps, although incandescent lighting creates a lot of heat and thus cannot be used in small, enclosed areas.  Metal, stone, and glass are generally not prone to deterioration due to light.  

Dust and other airborne pollutants can wear away surface detail and promote damage caused by other pollutants.  Sources include highway dust, wind-driven dust, wood smoke, and dirt from the floors of outbuildings or tracked in by visitors and staff.  Storing artifacts and artwork on the floor creates the potential for damage from water, rodents, molds, dirt, and dust.  Such poor storage practices also increase the chance that the object will be bumped into or stepped on.  

Currently, Commission staff dust all the displays and wipe and vacuum display cases at least once a year.  This takes three or four people several weeks to accomplish.  The desirability of dusting and cleaning the artifacts in building displays has been a matter of some debate, with some arguing that the dust provides historic ambiance.  Virginia City and Nevada City are not abandoned ghost towns, however, and the Commission has a mandate to preserve the artifacts.  Allowing them to remain in dirty conditions goes against this mandate because of the intrusion of deteriorating agents such as dust, insects, rodents, mold, mildew, and fungus.  

Pests such as silverfish, dermestids, moths, and powder-post beetles devour wool, wood, and cellulosic materials.  Rodents destroy objects by eating them or using them as nesting material.  Mice may lead to the risk of human exposure to the hanta virus.  Dead flies and other insects in windowsills attract dermestids, which later move into collections.  The collection is most threatened in this order: paper items such as labels, wallpaper samples, boxes, and newspapers; photographs; textiles; organic materials; and inorganic materials. 

A conservation assessment of the historic artifacts housed in twenty-nine buildings in Virginia City was performed in 1994.  The report provided broad conservation priorities for those resources (Nevada City was not examined).  

In 2000, two assessors outlined the conservation needs of the vehicle collection (wagons, buggies, fire wagons, coaches, and sleighs).  They determined that many pieces are in extremely critical condition and will likely deteriorate beyond repair within five to ten years.  Recommended intervention included storage in an environmentally controlled facility and treatment by a skilled conservator.  A few pieces that do not have enough left to conserve are candidates for complete reconstruction because of their historical significance.  The assessment also recommended regular annual maintenance of all the collection’s vehicles, including vacuuming the surfaces, removing debris, oiling selected wagons, and beginning conservation treatment on at least one vehicle each year.  

Guiding Principles: The key to long-term preservation of the collection is practicing preventive conservation.  This includes monitoring and controlling the display environments, applying proper storage and exhibit techniques, practicing proper handling, and implementing an ongoing housekeeping program.   

In almost all cases, the displays should dusted and cleaned or the artifacts will soon be in no condition to display and too far gone to be restored.  Depending on the interpretive goals, a few displays such as blacksmith shops might be left with some cobwebs and grease intact to give an air of realism (for example, a smoke-covered window could be interpreted as allowing the blacksmith to examine the color of the glow of heated metal for tempering the steel).  In general, both sides of the  window panes in all buildings with displays should be washed to facilitate visitor viewing and to showcase the resources, even if the historic building owner might not have done so. 

The windows of buildings containing artifacts should be fitted with protection that reduces damage from sunlight.   These might be opaque window shades or curtains, preferably of period-appropriate styles and materials, that are closed whenever the displays are not being viewed by the public or the staff does not need the lighting.  Ultraviolet shields such as Lexan panels might work, although they may create mirror or shadow effects and trap insects.  If used, they must be ventilated and easily removable. 

Diligent housekeeping, environmental monitoring, and integrated pest management will always be necessary for the Virginia City and Nevada City collections.  Poor housekeeping procedures accelerate deterioration of artifacts.  A written annual maintenance plan/housekeeping schedule for the entire collection is being developed as part of the Collections Management Plan.  Thorough cleanings should be done in the spring and fall in buildings with significant displays, as these are the critical seasons for pest control.  Vacuum dead flies in all collection areas on a regular basis.  Clean with low-suction vacuums (this requires electricity, however).  Other techniques can be used for fragile or porous items.  Those doing the cleaning should be well trained in the proper procedures.  The Commission should use insect and rodent traps to determine the presence, quantities, and entry points of insects and rodents.  Make sure that all pest control measures follow the principles of Integrated Pest Management.  The Commission should consider enclosing some displays that are currently exposed to dust and insects.  This can be a very costly option, however. 

Another preventive conservation measure is rotating objects between storage and display.  Artifacts in most of the building displays, particularly textiles and other rather fragile items, should be rotated in order to protect the resources.  This can be accomplished by removing some of the many duplicate items in store displays, for example, and cleaning, repairing, and storing the ones not on display in the curatorial center.  Some furnishings might be changed annually, others on a much less frequent basis.  Certain displays have exceptional significance just as they are, such as the McGovern Store, so rather than rotating artifacts, steps should be taken to protect them from light, dust, and pests.  The decision on rotating artifacts must be made on a building-by-building basis. 

The treatment of artifacts displayed in an uncontrolled historic structure is often the least cost-effective conservation dollar spent.  The more objects placed on exhibit, the higher the treatment costs.  Conservation treatments that go beyond stabilization are required in Virginia City and Nevada City, however, because of the exhibits that feature furnished interiors.  Deciding which artifacts to protect with improved storage conditions, which to do conservation work on, and which to restore is complicated.  Curatorial resources should be spread as equally as possible over the collection, including both the economically valuable objects and those that are less “glamorous” but also significant, such as mining- and transportation-related items.   

Criteria for determining whether to do preventive work, conservation work, or restoration of a particular artifact include: 

• Artifact condition and material type
• Association with Virginia City and Nevada City
• Historical significance
• Availability of similar items
• Interpretive potential
• Value
• Cost of conservation

Historic artifacts located in the mining landscape may be either managed on-site or removed for storage or display in a more controlled environment.  If vandalism is not a significant concern, then some artifacts may be left on their original site both to adhere to the principle of “doing no harm” and to allow for provocative interpretation.  Before determining a policy for these artifacts, the Commission should discuss the issues with managers of Klondike Gold Rush National Historical Park in Alaska; many artifacts in that park have been left in place along the Chilkoot Trail. 

A qualified conservator should prepare a comprehensive conservation assessment for the entire collection, once the immediate needs of the most-threatened artifacts have been taken care of.  This will establish priorities for conservation treatment of specific items.  It will also establish a schedule for completing conservation treatment on specific artifacts. 

Priorities for treating artifacts should take into account their potential use in interpretive programs.  Thus, a kitchen stove owned by Nevada City’s Finney family would be of higher priority than a relatively common sheepherder’s stove from the 1930s, all other factors being equal, even if the sheepherder’s stove had a much higher monetary value. 

The Commission should establish regular monitoring of environmental conditions.  For example, install hygrothermographs in key display and storage areas to record humidity and temperature changes over time.  Keep logs of daily observations and of weather.  This information will help in planning for retrofitting and prioritizing and will help assess the effectiveness of any environmental control measures. 

Options to Consider:  

Ø                  To obtain more environmentally controlled storage space, build enclosures around items that were stored in better conditions. Acquire modular sealed storage units such as a Bally building for storing vulnerable items within an existing building(s) that is large enough for this purpose.  Bally buildings provide a virtually air-tight environment in which a museum environment can be maintained. 

Ø                  Install climate-controlled exhibit cabinets to display certain fragile or valuable artifacts.  These might not be appropriate in the furnished building displays, but they would certainly be appropriate for interpretive exhibits, whether in the visitor center or elsewhere.