Those who have been in the museum field awhile have surely noticed an evolution in professional standards over time. Conservation know-how is one area especially prone to obsolescence. For instance, years ago a conservator recommended polishing brass with wenol to one of our staff members who then worked at an historic house. Current advice, however, acknowledges that wenol contains ammonia, which is harmful for brass.
Dressing leather with neatsfoot oil, or some other product, used to be a routine part of professional care. In contrast, conservators today have documented the build-up of grime and outbreaks of fatty bloom as potential effects of these treatments years after application. Most now recommend preventative conservation measures for leather, such as storage in a regulated environment and dusting with a soft brush.
Similarly, our recent Wood & Metals Workshop participants heard from Conservator Jane Bynon that problems with decades’ old archaeological treatments have prompted British conservators to rethink unearthing materials in the first place. It may be best to leave known artifacts in the ground or under water in an environment that has allowed their preservation thus far, rather than removing them and initiating a series of treatments. As careful as conservators try to be, loss is often involved in treatments. The ideal of reversibility frequently translates into the reality of re-treatability. Some in the archaeological branch of the field question whether routine cleaning is ethical. Even the simple process of brushing dirt off a shard removes irreplaceable contextual information and evidence of the artifact’s history.
For those responsible for museum collections, then, the lesson of obsolescence should not provoke mistrust in conservators. Rather it should be a caution to undertake any kind of treatment without education, research, training, and experience. Seek advice from those you know to be knowledgeable; gathering multiple opinions will inform your decisions more thoroughly. Most importantly, work to establish storage environments that will promote preservation: managing light, temperature, and RH levels and protecting artifacts from pests and pollutants. With good collections care practices, artifact treatments will still be necessary, but less (handling and solution applications) is usually more.