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Fossil Shell Cleaning

After a hard day's search for fossils, there is still work to be done; the shells you̵7;ve collected must be cleaned. In order to clearly view the intricacies of the fossil shells and prepare them for display, you̵7;ll need to think beyond soap and water. You can choose from a variety of methods to select the one best suited for each individual fossil.

Toothbrush and Water
- Brachiopods will usually respond well to a good cleaning with just a toothbrush, water and a small amount of dishwashing detergent. The shell must be in good condition with only mud and loose matrix, the material in which the fossil is imbedded. Use a few drops of a dishwashing detergent to one cup of water and gently scrub the shell. A word of caution: using this method on a fossil shell that has cracks may cause a brachiopod to break or dissolve.
Dental Tools
- Another method for cleaning fossils is to use hardened steel picks and scrapers such as those dentists use to remove tartar from teeth. This method works well but is time consuming. Use a steel pick and a magnifying glass to remove matrix from the fine lines in the fossil. A hardened steel scraper is effective in removing soft shale adhered to the shell.
Pneumatic Hammer
- For shells that are buried in rock, use a pneumatic hammer, a miniature version of the jackhammers used by construction workers to break up rock. The pneumatic hammer will break through rock, exposing the fossil shell. These pneumatic hammers are tiny and must be used under magnification in order to remove just the rock and not damage the fossil. A tiny misguided movement can ruin a shell.
Micro Sandblaster
- Remove soft rock and shale by using a micro sandblaster. This machine uses high air pressure to force a fine powder through a nozzle, blasting away soft rock without damaging the harder fossil shell. The hardness of the rock and the imbedded shell will determine the size of the nozzle and the abrasiveness of the powder used in the micro sandblaster. Start with the finest nozzle and powder and work up to more abrasive amounts. Using pressure that is too high and highly abrasive power can cause damage to the fossil shell. Do this work under a microscope while wearing protective glasses and a filter mask.
High-Speed Rotary Tool
- There are many brands of high-speed rotary tools on the market, such as the Dremel tool, that can be used effectively in cleaning fossil shells. Use a high-speed tool to grind away chisel marks caused by the airhammer. You can also use a polishing tip on a high-speed rotary tool with some fine jeweler̵7;s rouge to polish the newly cleaned fossil shell.

Fossil Collecting