Old post, but, with our DLH cat, when she got the clumpies (she doesn't anymore, thankfully) I actually had one of those "personal groomers". They're really gentle, they don't pull hair if you do it right, and they're basically silent. Plus, you have more control as to where you shave the cat, because they're small (about the size of a sharpie marker), so if they're long hair, you can usually get away with shaving a clumpie without being able to tell that you shaved it out.