Velcro can quickly become full of fuzz, thread and hair. I have found the easiest and most effective way to clean Velcro is by using a strong fine tooth comb, preferably a metal one as the teeth won't bend as easily. In order to keep it relatively free of these foreign objects, it is best to keep it 'done up' as much as possible. The worst place to get Velcro full of 'stuff' is in the washing machine and dryer. Even if it is closed when put in, the agitation of the machine often pulls it apart and it becomes embedded with fuzz, hair and threads.