I have had my first sphynx (my first cat ever) for about 4 months now. When I got him from a young lady who was moving, his nails were black and caked, looked awful. I have been cleaning them and they look great, except for one thing. They keep splintering, like layers coming off. He cries when I trim them and it seems to split them even more. I have tried different cutters from different stores, and none seem to work, what could be wrong? Any advice would be greatly appreciated. Thanks..