I use the stiff brush routinely -- dry --as a stylus cleaner. Very useful. You do need to be gentle with it (and always back to front), but I've never damaged a stylus and it's much more effective than a soft brush.
On the other hand, I don't use the #9 cleaner much at all. :-)
On the other hand, I don't use the #9 cleaner much at all. :-)