You can, but fingers push product onto the surface rather than working it through the hair shaft. The Treatment Brush combs product into each section more thoroughly and usually means you need less product per wash, which adds up over time.

Yes. Section the hair first and work through each section individually rather than applying to all hair at once. The time saving against hand application is more noticeable the longer and thicker the hair.

Rinse under warm water immediately after use while product is still wet. Most treatments wash out easily. For oil-based treatments, a small amount of shampoo on the bristles clears any residue. Leave bristle-side down to air dry.