iPod How to get rid of iPod nano on iTunes???

ok, i bought a blue ipod nano, and i connected it to iTunes, put all my stuff on it. then just today, i went out and exchanged it for an orange one, now when i connect it, the blue one AND the orange one botth show up on itunes, how do i get rid of the blue one for good? thanks!

well that problem is solved, but now when i go to songs on the new ipod, the songs are all grayed out, and unclickable/playable/removable, what do i do now?

wow, i feel like a n00b lol, you have to click manually manage music, ok thx for da help, but im good now