What is the recommended substance for removing a colony of odorous ants from the wall?

Boric acid dust is the recommended substance for removing a colony of odorous ants from the wall due to its effectiveness as a slow-acting insecticide. When ants come into contact with boric acid, they carry it back to their colony and share it with other ants, eventually leading to the elimination of the entire colony, including the queen. It's particularly useful for targeting hidden nests, such as those often found in walls.

The other options do not possess the same level of efficacy for eliminating ant colonies. Diatomaceous earth, while useful as a desiccant to kill insects, requires direct contact and may not be practical for treating hidden colonies effectively. Coffee grounds and vinegar might deter or repel ants temporarily, but they do not eliminate colonies and may not address the problem at its source. Thus, boric acid dust stands out as the most effective and recommended choice for targeting odorous ants in walls.