I was hand sanding with 800, then 1500 grit. I wasn't trying to remove all the chrome from the entire outside; but I'm guessing you could do the whole job in less than half an hour.
Thinking about this a bit, and here's what I would have on hand to do it: 1 sheet ea. of 400, 600, 800, 1500 grit sand paper. Something soft but flat like a pad of paper, or a mouse pad. Lay the sandpaper down on the pad, and hold the atty down on it to rub. I wouldn't use the 400 or 600 unless the chrome is unwilling to sand off easily. Whichever grit takes the chrome off, the rest are just needed to take out the scratches you put in it with the first grit. The higher the first effective grit, the more sheets of it you'll need to get it done. (400=1sht., 600=2, 800-I'd get 3 sheets, just in case)