You need to take it somewhere to a detail place that can use a orbital buffer to bring the paint back to new.
What they will do in a few hours will take you a entire weekend by hand.
My silver car was faded really bad about 4 years ago, i spent 100.00 and the guy spent 5 hours bring the paint back up to snuff.
Before taking it in, i attempted by hand to use some Mequiers cleaner to take out the oxidation, it worked but i spent about an hour on 1/2 of the decklid.
He did the work with 3 different style orbital pads, and it turned out 10 times better than i could have done.
Plus for the amount of money i spent it was worth 1/2 the day to sit back and do something else.
If your going to do it by hand, get ready for tennis elbow!
BW