What type of brush should be used to clean areas that are hard to reach in the receiver assembly?

Using a soft brush for cleaning areas that are hard to reach in the receiver assembly is ideal because it effectively removes dirt and debris without risking damage to sensitive components or finishes. Soft brushes provide the necessary flexibility to navigate tight spaces while being gentle enough to avoid scratching or wearing down surfaces.

A metal brush, on the other hand, can be too abrasive for delicate metals or finishes, potentially causing harm. While a paintbrush could manage some cleaning, it typically lacks the stiffness needed to dislodge grime in tight spots effectively. A toothbrush, while commonly used and somewhat effective, may not have the specific bristle softness or shape that a dedicated soft brush designed for firearms cleaning can provide, particularly in intricate areas of the receiver assembly. Therefore, the use of a soft brush strikes the right balance between effectiveness and safety for maintaining the firearm's integrity.