Collection Contaminants
Sometimes collection items can be hazardous - both to your health and the long-term preservation of other objects. Felted or green-dyed items may contain mercury or arsenic; taxidermy and other organics may absorb pesticides; and old treatments from the early days of conservation often don't stand the test of time. This document from the US Department of the Interior discusses common contaminants, how to detect them, and what to do with the objects: https://www.doi.gov/sites/doi.gov/files/migrated/museum/upload/Contaminated_Collections_FAQs.pdf