I have a few metal covers on the walls in my house. These covers are ugly can I eliminate them?

The metal covers are likely there for either future connections of cable or phone or they could be concealing electrical connections. The electrical code states that a junction in an electrical circuit must be accessible. Sometimes a junction box is necessary if a wire is damaged or too short to reach its destination. This box must be accessible in case there is ever a problem. If the box is in a wall you will see a metal or plastic cover. If the connection and box is in a ceiling it can be above a drop ceiling panel because you can move the panel to access the box. It may be tempting to conceal the box but I would not recommend it. It is far better to be able to check the connection if there is evidence of a problem.