Detailed Procedure:

 

To collect metal filings and shavings:

1. Photograph the filings or shavings in place.

2. Wear eye protection, breathing protection, and new, unused, clean latex or nitrile gloves.

3. Using a new brush or other tool, collect the particles into a plastic bag, pillbox, or vial. Do not use metallic containers or metallic collection tools. If needed, brush the fragments onto a clean sheet of white paper, then fold the paper pharmacy style and place the folded sheet into an envelope. Avoid using tape lifts. Collect each location of metal filings/shavings separately and package separately. DO NOT MIX PARTICLES FROM DIFFERENT AREAS OR FROM DIFFERENT TOOLS.

4. Seal the container with evidence tape. Initial and date the tape.

5. Label the container with identifying information, including case number, date, exhibit number, a brief description, and your name.

6. Store the item in a secure location, such as a locked evidence van or your vehicle, until you are able to transport it to the laboratory.

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Laboratory testing of metal filings and shavings:

Metal objects may be associated through toolmark comparisons. When toolmarks are not present, chemical and/or instrumental analysis can be used to compare questioned and known items. Very small pieces may only be able to be classified by element or alloy. In larger samples, trace element composition may be identified and possible traced to a manufacturer and/or lot.

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Source:

Crime Scene and Evidence Collection Handbook. Bureau of Alcohol, Tobacco, Firearms and Explosives. 2005.