Which leukocytes are sometimes referred to as "housekeeping" phagocytes because of their role in clearing (cleaning up) cell debris?

The answer is Macrophages. White blood cells also the leukocytes are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from multipotent cells in the bone marrow known as the hematopoietic stem cells. Macrophages are important cells of the immune system that are formed in response to an infection or accumulating damaged or dead cells. They are large, specialized cells that recognize, engulf and destroy target cells.

Macrophages. Macrophages are a type of white blood cell, of the immune system, that engulfs and digests cellular debris, foreign substances, microbes, cancer cells, and anything else that does not have the type of proteins specific to healthy body cells on its surface in a process called phagocytosis. These large phagocytes are found in essentially all tissues, where they patrol for potential pathogens by amoeboid movement. They take various forms throughout the body, but all are part of the mononuclear phagocyte system. Besides phagocytosis, they play a critical role in nonspecific defense and also help initiate specific defense mechanisms by recruiting other immune cells such as lymphocytes.