What should be done to spent cartridge cases after collecting for evidence?

Wrapping spent cartridge cases in cotton or filter paper after processing for prints is the appropriate method for ensuring their integrity and minimizing contamination. This practice protects the delicate surfaces of the cartridge cases that may contain valuable fingerprints or other trace evidence. Using cotton or filter paper provides cushioning and prevents any direct contact with harsher materials that could alter or damage the evidence.

Additionally, employing such a method keeps the sample stable during transport and storage. Keeping the cases sheltered from external elements, including moisture and dust, also contributes to the preservation of potential forensic evidence.

The other options, while they have merit in certain contexts, do not prioritize the need for preservation of potential evidentiary details as effectively as wrapping in cotton or filter paper. Using plastic evidence bags, for instance, may create a static charge that could potentially compromise trace evidence, while a cardboard box, although sturdy, may not provide adequate cushioning. Packaging separately in clear bags might be beneficial for organization but does not offer the same level of protection for the surface of the cartridge cases.