AIC's 52nd Annual Meeting

Thorns are a practical and effective cleaning tool for soft metals like gold and gilt surfaces. Previous literature about their use in conservation either lacks detail on where to source thorns or recommends species that are unavailable in the United States.

The Maryland Archaeological Conservation (MAC) Laboratory sits within the 560 acres of Jefferson Patterson Park and Museum (JPPM) in southern Maryland. The park features grass, wildflower, and agricultural fields, plus wetlands, riverfront beaches, and forested land. With guidance from the park’s horticulturist, two types of thorns (black locust and greenbrier) foraged at the park were tested for their use in the conservation lab. Criteria were developed for selecting thorny plants as well as basic procedures for harvesting, processing, and using thorns as handheld cleaning tools.

While this research focuses on plants available in the mid-Atlantic, these species are common (or invasive) across the United States and Canada. Purchasing thorns online may be expensive, result in inconsistent quality, and have questionable (or illegal) sourcing. Finding a local source for thorns, and foraging in a sustainable way, can benefit the environment while also providing free disposable tools for a busy conservation lab.