I just pull out the hair/wipe off the dander whenever it seems necessary. I have never put any sort of cleaning solution on my brushes. The only thing that gets on my brushes is my own horse's hair and dander, so I don't feel a need to disinfect them. If my horse had some sort of rain rot/fungus I certainly would clean the brushes. Plus, my horse has very sensitive skin (he has gotten hives from rolling in new shavings and rolling in new arena footing) so I don't want to run the risk of getting any irritating cleaning solutions into his skin.
"The trouble with the world is that the stupid are certain and the intelligent are full of doubt"