Keylight trouble, black hair is dancing

[Blade Borge]

I tried clipping the blacks and white but can't seem to get rid of the weird dancing action on black hair, you know, where it looks all artifacty going from black to slight green.

 

[gdiguy]

Try isolating the problem area with a mask and dedicate its own key; this will allow you to tweak the settings that are optimal for that section of the shot. You might also try using a track matte, I find these are very useful at times to wrangle a bit more control. If you can post the specifics of your shot (such as format shot in or even a screen shot itself), other solutions may present themselves with the additional data. Good luck!