How to Clean and Preserve Your Fossil Shark Teeth

Rinse finds in clean water as soon as reasonably possible — salt and sand abrasion continue working on specimens until they are cleaned. A saltwater rinse in the field is fine; a freshwater rinse at home is the goal before any drying. Do not use hot water on freshly collected specimens: rapid temperature change can stress the crystalline structure of mineralized fossils, particularly any with thin enamel or pre-existing micro-cracks.

Transport significant finds in containers that prevent tooth-on-tooth contact. A single plastic bag with multiple loose teeth is a recipe for chipped enamel and broken roots. Individual zip-top bags, compartmentalized tackle boxes, or fabric-lined containers protect specimens in transit. For large or structurally vulnerable specimens (roots that have partially separated, delicate vertebrae), wrap briefly in a damp paper towel or cloth to prevent dehydration cracking during the trip home.

The majority of fully mineralized Miocene shark teeth need nothing more than a soft toothbrush and warm water. Work under running water, brushing in the direction of natural features — along serration valleys, down the root groove — rather than against them. Gentle circular scrubbing is appropriate for the flat enamel surface.

Stubborn matrix — cemented sand, silt, or calcium carbonate crust — can be addressed carefully with a wooden skewer or bamboo pick (both soft enough not to scratch enamel) or a stainless dental pick for material lodged in crevices. For calcite or carbonate crust on Florida Miocene teeth (not on carbonate-rich specimens from South Carolina Eocene sites), brief treatment with dilute white vinegar (5% acetic acid) or a dilute citric acid solution will dissolve the crust without harming the fluorapatite of the tooth. Rinse thoroughly immediately after acid treatment. Never use acid on teeth from carbonate-dominated formations (Ashley Formation, some Calvert specimens) where the tooth itself may contain significant calcium carbonate.

Some teeth — particularly river-washed specimens that have experienced more physical stress, or specimens from less well-mineralized horizons — show early-stage cracking, flaking enamel, or a chalky, powdery surface. These require consolidation before cleaning proceeds.

Paraloid B-72 dissolved in acetone (at 2–5% concentration for initial treatment, up to 15% for heavier consolidation) is the conservation gold standard used by major natural history museums worldwide. It is a thermoplastic acrylic resin that penetrates fossil pores, consolidates friable surfaces, and dries completely clear without yellowing. It is also fully reversible — additional acetone re-dissolves it if subsequent treatment is needed.

Apply thin consolidant by brush or dropper, working from the most fragile surface inward. Allow each coat to fully cure (acetone to fully evaporate) before applying the next. Multiple thin coats are far better than one thick coat, which can trap air bubbles and cause surface irregularity. Do not wet very fragile specimens with water before consolidation: rapid water uptake can cause clay minerals within the matrix to expand, further stressing the fossil.

Well-mineralized fossil shark teeth are inherently stable and require no ongoing special treatment once clean and dry. Store in an environment with moderate, stable humidity — avoid attics or uninsulated garages where humidity swings dramatically — and shield from prolonged direct UV exposure, which can bleach some mineral surfaces and degrade organic consolidants over time.

Standard riker mounts (shallow glass-topped display frames with cotton batting) protect smaller specimens while allowing easy viewing. Museum-quality acrylic boxes with UV-filtering glazing are available for more valuable specimens. For a growing collection, the professional approach is compartmentalized specimen trays with cotton batting and individual paper labels.

Labeling matters more than most new collectors realize. A tooth without provenance data loses significant scientific and personal value over time — you will not remember which beach, which storm, which year. Record at minimum: collection locality (beach name, river reach, county, state), collection date, and your best identification of geological formation and species. Even a small paper label kept with each specimen preserves the story the fossil carries.