Chemical sanitizing solutions do most of the disinfection work in a milking machine's cleaning routine, but they're not a substitute for physically scrubbing out milk fat residue and buildup inside tubing, claws, and cans — narrow tubing especially can develop a film that a rinse alone won't fully remove, and that residue is exactly what harbors bacteria between sessions. The Brush Set gives you the right shapes and sizes for each part of the system, since a single brush shape doesn't work well across tubing, claw interiors, and can walls.
This isn't a part that fails or wears out mechanically the way a gasket or belt does — it's a consumable hygiene tool that needs periodic replacement simply because bristles wear down and lose their scrubbing effectiveness with regular daily use, at which point they stop doing their job even though nothing about the brush looks obviously "broken."