Re: heavy oxidation
i'd try 1000 grit for starters and see how that works. it looks pretty faded, you might need 800 or even 600. the problem with more aggressive grit is that you need to follow up with lesser grits to smooth things out. if you use 600 you'd need to follow up with 1000 and then 1500 or 2000. if 1000 works from the beginning, then hit it with 1500 or 2000 afterward.
but, there's always a catch, you really should follow the sanding with compounding and then wax. if you really want it to pop, use polish after the compound ('finesse it' is awesome, and expensive but it works great).
alot depends on how good you want it to look and how much time you want to spend. there are bunches of threads on this if you search.