I did my 750 covers with a buffing wheel and several different compounds.
It's helpful to have at least two different sized wheels. (Small & larger)
I didn't need to sand but my covers weren't too bad to start.
I used brake cleaner/acetone to strip off the remaining clear coat.
For my XS650 I had to strip and sand prior to buffing.
The aluminum was more badly oxidized and Yamaha didn't spend as much time finishing at the factory as Honda did.
(The fork lowers were especially rough compared to any Honda I've ever seen.)
For the 650 I started wet sanding with 800 and worked up to 2000 then buffed.
I hate polishing...