That was a regular binder clip. I would think that would be too strong to use. However, maybe I should try it on mine. Bruce always has to help me when I clip their nails and he is horrible at scruffing them. I have those large clips at work. Maybe I could find one that isn't quite so strong.

This video was done at a vets office, and they didn't leave it on the kitty too long. So I don't think it was cruel.