A quick way to remove the greenish color: add the secondary color correction to the event (or to the whole track or project).
In the popup window that opens, you find 1 colorwheel.
Beneath the colorwheel are two pipets.
Click on the left pipet. Your mouse becomes visible as a pipet. Click with your mouse (the pipet shape) in your preview window on a part that is supposed to be black. The greenish color will disappear.
If you are not satisfied with the result, just reset the effect (doubleclick on the white dot in the colorwheel) and repeat on another black spot in the preview window.
Theo