This is a preset that you can use on green screen footage or just general compositing.

YY_MagicKey is a very powerful keying plugin, minus the complicated settings. It was designed specifically with the keying-out of premultiplied stock elements (explosions, blood, muzzle flares, etc) in mind, and never takes a long time to set up.

A quick tip on creating "super tight" garbage mattes to aid keying.

The Difference Matte effect creates a transparency a mask or a matte by comparing the pixels in a source layer with the pixel in a defined difference layer, and then keying out (eliminating) pixels in the source layer that match both the position and color in the difference layer.