To vacuum hard-to-reach areas, which attachment should be used on the vacuum hose?

Using the crevice tool is the most effective choice for vacuuming hard-to-reach areas. This attachment is specifically designed to fit into narrow and difficult spaces, allowing for effective suction and removal of dirt and debris that accumulates in places like between cushions, along baseboards, or in corners.

The crevice tool's elongated and narrow shape enables it to access tight spots that other attachments may not fit into, ensuring a thorough cleaning process. In contrast, while the dusting brush can be useful for delicate surfaces and larger areas, it does not provide the targeted suction needed for confined spaces. Similarly, the upholstery nozzle is better suited for cleaning fabric surfaces rather than tight gaps, and the extension wand, while helpful for reaching high areas, lacks the ability to effectively clean small crevices. Thus, the crevice tool is the optimal choice for this specific task.