You are looking at part of a dirty register.  These exist in all sorts of buildings, and if yours  does not resemble this exactly, consider the fact that this is part of an air conveyance system, and whatever form you have can have accumulated this much debris.

At Mighty Duct we service residential, commercial and industrial properties. We clean air conveyance systems....this means we clean air ducts, vents, exhausts, or whatever moves air around. 

Our goal is to provide you with good indoor air quality and reduce the risk of fire or health hazards from kitchen exhausts, dryer vent accumulations, and even other forms of commercial exhaust accumulations that can be costly or offensive.

From a residential perspective most families, unknowingly, pay more for cable TV than they do to improve the air quality of their homes.

We are so worried about the quality of food that we feed our children. Yet we need to also be concerned about contaminated air, you must have read about "sick buildings." We have actually seen it, know it's true, and work every day to make the problem go away.

Many allergies are due to molds and mildew that can harbor in air ducts and registers, while not seen, they can create great discomfort for your family.

New homes are not free from debris in the ductwork. Oftentimes during construction sawdust or drywall dust is drawn into the system. Here it stays creating a breeding ground for molds and mildew. Odors aside, the health risks need to be considered.