I plan to buy this East wood polisher http://www.eastwood.com/ew-buff-motor-1 ... f-kit.html to polish some stuff on my engine. Alternator and Vale covers so on.... I did a test with sand paper I think the polisher will do a good job.
when polishing anything you start with the sandpaper thats closest to the texture your polishing
if its smooth you can start with 300 or 400,then after its all consistant you step up to 500 then 800 then 1000
1500,3000 then polish with a medium polish then glaze the finest compound.
i do this on headlights at the dealership
yours looks to be a good start
i dont use high speed on paint or plastic
at the end you should seal up the AL.
you can use clear coat,3 good coats
dont paint the connector