I would be very careful in trying to remove what is basically a cosmetic problem using anything abrasive to "even out" any scratches as this could harm the screen whilst doing so.
I would suggest "kill two birds with one stone" and buy yourself Apple's own case. They not only work perfectly with your iPad but also fit so nicely that all the aluminium alloy edges, scratched or otherwise, are completely hidden. The leather one, though not cheap, is beautifully tactile and a joy to hold.