honestly i have no idea, I would think they'd be ok for practice and that you would want to clean your marker out really well afterwards. would hitting them with a blow dryer (not on hot, on just fan) get some of the hair off?
Lover of All Things Paintball
I was thinking that you should probably use NAIR on your balls. It is supposed to disintegrate hair so all you have to do is wipe it off. Looking back on it now, I don't think you should roll your balls across velcro.
Also looking back on it, why is there cat hair on your balls?