If you don't have access to a Porter Cable random orbital polisher and the appropriate foam pad + polish, you can safely try Meguiar's Scratch X (by hand).
You can go to
www.meguiarsonline.com and search for the threads for properly applying Scratch X. I've removed some pretty awful scuffs, etched bird poop, etc using this product and it really works well (but follow the directions posted to the letter). Following the removal, apply some good quality wax (Meg's NXT, Pinnacle, etc).
Hope this helps.
Totoland Mach