that needs a full refinishing. you'd be better off just getting a new wheel, it'll never match the other ones on your car unless you take it somewhere to get the face machined, since that's how they came. and at that point, that's a huge waste of money on an oem wheel. i'm sure you can find one on ebay.
if you want to paint them white, sanding will work, but you'd have to start off with a heavy grit and work down to something fine, so you won't see the scratches through the paint. i'm not really for painting oem wheels though, especially smaller ones...they just never look right and end up looking cheap. that's also still a lot of work for a whole bunch of nothing as well.