I pulled the front of the radio off, pulled the circuit board off of the front plastic, and sprayed electronic cleaner on everything (except the screen, don't get any cleaner on the screen). On the potentiometers I turned them while spraying, on the switches and buttons I pushed them while spraying, to help clean everything. I think the reason it sounded better after was because I had scratchy volume knob. After I cleaned it the connection inside that potentionmeter was a lot better. If your stereo is working properly I wouldn't bother doing it. Remember this was all on the stock Radio\CD player.
I did a more in depth surgery on my Sony headunit, but thats a different story, lol.