by the main grounding strap ?? or clean the actual main ground ??

 

You can buy the faceplate kit (aka the plastic panel to fill the "dead zone" so that wires don't show) at Wal-Mart.

Believe it or not, WM carries Scoche faceplate kits, which are a reputable brand, same as the ones that most chain stereo shops carry (Circuit City / Best Buy).