Lots of options here, including:
1. If near the edge, use Motion to zoom in enough so that you can fill the screen with the bad part out of sight. Downside = some loss of definition.
2. Place something on top of the unwanted area.
3. Rotoscope (After Effects or PhotoShop) to paint over the unwanted part. Tedious and time consuming.
4. Blur out the unwanted area using a copy of the base footage and a track, image or garbage matte to isolate the area to be affected.