Non-destructive, safe removal of conductive metal coatings from fossils: a new solution

Scanning electron microscopy, and some other imaging techniques, commonly require that specimens to be imaged are coated with a conductive metal, such as gold, gold-palladium, platinum or silver. However, the application of metal coatings changes the appearance of specimens and can obscure important features, and thus may be undesirable, or even prohibited by institutions or curators. We describe a harmless, straightforward and inexpensive technique for removing gold. The method involves immersing samples in ionic liquids and rinsing in water. No further handling is needed, no poisonous compounds are utilised in the process, and the liquids may be tailored to remove other metal coatings without affecting the adhesive used to attach the specimen to the substrate