What type of container is appropriate for collecting evidence containing ignitable fluids?

When collecting evidence that may contain ignitable fluids, it is critical to use a container that prevents the evaporation of those fluids and minimizes any potential chemical change to the evidence. Glass jars with metal screw tops are particularly appropriate for this purpose for several reasons.

Firstly, glass is inert and does not react with the ignitable fluids, ensuring the integrity of the evidence remains intact. The metal screw tops create an airtight seal, which effectively slows down the evaporation of volatile substances that are often present in ignitable fluids. This is essential since evaporation can alter the composition of the evidence, making it less reliable for analysis.

In contrast, other containers like plastic bags are not suitable because they can allow vapors to escape, potentially altering the evidence. Paper can absorb moisture and may also introduce contaminants that compromise the sample. Cardboard boxes, while sturdy, can also be permeable and could allow vapors to present in the evidence to escape, making them less ideal for storing ignitable fluids.

Thus, using glass jars with metal tops is the best practice in forensic science for collecting and preserving evidence that may contain ignitable fluids, ensuring that the evidence remains uncontaminated and suitable for analysis.