The brushes on my Host reliant get absolutely filthy after a while. I have to clean them because if i dont and i use it to agitate on a white carpet i get lots of little black water marks on it, luckily the brushes on the Host reliant do not have any moving parts that can be damaged by water, at least i cant see any, so i give them a soak in a bucket with detergent in and they come up like new, dont know how i would manage if i could not remove the dirt that builds up at the base of the brushes.