The scattering happens when both paint dries too close to the ferrule, and a normal reaction with natural fibers. It happens to nylon brushes too, but a bit slower.
91% alcohol will dissolve most hard to get at paint, but in time wreaks havoc on the fibers. When you're done with painting, a good idea is to dip them in clean water, form a point as best you can, and have them dry that way. Eventually all brushes fray and scatter, but they'll still be very useful for your drybrushing needs.
Oh, and errant hairs that stick out way to far to be smoothed, there is no harm in just clipping these off.
Hope this helps some. If you could see nearly all of our workstations for customizing, you'd find quite a few of us in the same boat.
_________________
Sometimes, the mad are driven that way.
http://capolan.tripod.com/- Some Stuff.