Halo removal.

[Gandalf]

What filter(s) should I use to remove the 'halo' effect from videos? In other words, after I remove the 'noise' from my videos, I notice what looks like a sort of 'halo' effect in areas where there is supposed to be a gradual difference in color shading/brightness, or whenever a bright colored object is near, or right next to, a dark colored object. Any suggestions?