Laboratory techniques

Handling and cleaning loose archaeological or fossil teeth

Primate teeth are small, smooth, rounded and difficult to grip. Fossils can be delicate, so pad the table with a foam sheet in case they fall. A small tray of dry sand holds them gently in position under a camera or microscope; black sand from aquarium suppliers provides a good visual contrast. It is safest to use fingers for handling, but fine forceps can be useful, especially the tweezers used in electronics, which have plastic tips that don’t scratch. Good light is essential: from a window behind the bench, a bright desk lamp or, in the field, a head torch.

Labelling is vital, but teeth should never be marked directly. It is safest to keep each tooth separate in a small Ziploc polythene bag containing its label (a Tyvek label written with permanent black marker pen). Perforate the bag ten times to provide ventilation, but keep it zipped up tight or the tooth will become separated from its label. Keep a photographic catalogue of the teeth with their labels in view to sort out mix-ups. The tooth bags can be kept in a lidded polythene box, with ventilation holes drilled just below where the lid clips on. Thin sheets of polythene foam (Jiffy Foam or similar) help to pad them. This system works well for all teeth and bones, with foam sheets cut to fit inside the bags. Clear bags show the contents on one side and the labels on the other side of the foam, so it is not necessary to open the bag to check what is inside. The less the specimens are handled, the better. Avoid centrally heated or air-conditioned stores, which are too dry and can cause dentine to crack over time.