Final answer:
A photocopy trash mark is an unwanted mark on a photocopy, caused by debris on the copier's glass or the original document, which can be reduced by cleaning the affected areas.
Step-by-step explanation:
A photocopy trash mark is an unwanted mark that appears on a photocopy, typically resulting from dust, dirt, or other debris on the surface of the photocopier's scanner glass or the original document being copied.
These marks occur when the photocopier's imaging system picks up not only the information meant to be copied but also any extraneous material present that reflects light differently than the surrounding area. Often, the appearance of such marks can be reduced or eliminated by cleaning the glass of the copier thoroughly before use.