Use a decorative screen to cover up the old fireplace footing. Metal screens work well with more contemporary decor, and printed paper screens work best with traditional styles. For more eclectic or transitional looks, consider using a frosted or painted glass screen.
Hang floor-to-ceiling curtains over the old fireplace footing if you have windows in the area. This works particularly well if you have a half window above the fireplace footing, but even if your windows stop a few feet before the old fireplace footing you want to cover, you can extend the curtains anyway to add visual depth to the room.
Put a potted plant in a decorative planter in front of the old fireplace footing. If the footing is tall instead of long, use a real or high-quality silk tree in a circular pot. If the old fireplace footing is on the long side, use a natural or painted cast-iron planter that's long with decorative flowers in it. Try to match the style of plant or flower to the decor in your home to complement the colors you're already using.
Paint the old fireplace footing the same color as your wall so it's difficult to notice. If you wish, you can still cover the fireplace footing with a decorative object to further obscure it from view.