When two items come in contact with each other, the harder item can leave an impressed or striated mark on the softer item. However, depending on the how the harder item was constructed, these marks may or may not be used for identification purposes. Toolmarks are sometimes referred to as striations, cuts, stabs, gouges, abrasions, scratches, indentations or compressions. Some examples of tool marks are: slashed tires by knife, indented hammer strikes on door, pried open window, cut wires or fencing, severed chains and picked locks.
Additionally, extrusions marks are found on most plastic bags. These marks from the manufacturing process can link a bag back to a roll or box of bags or two torn pieces of plastic bag to each other.
FoCoSS Forensics can perform scientific examinations in this area or we can review cases involving this type of examination and the reported opinions based on the results.