Hi,
I have tried and successfully remove the scratch from iphone back and the chrome bezel.
This is the product i'm using. it is a metal polish product call "autosol" and "braso". it can be use both on the metal bezel and the back plastic.
it only cause you around 7-10 ringgit each.
But several precaution need to be noted.
1) remove hair line scratches - sometime u see as hairline but it is deep. therefore if u polish it it will make it more obvious. but no worry keep doing it and it will clear in no time.
2) Must apply some pressure. Somehow i think this black casing is quite hard.
3) if it is a deep scratch. use very very fine sand paper. sand it first then continue to use autosol to polish it. dun worry .. autosol will remove the tiny scratches.
4) Apple logo and wording is printed. so dun use sand paper on this area and do not polish this area so much. however in my case i take the risk because my apple logo have many hairline scratches. i use autosol to polish it as well. it successfully remove 70-80 % of the scratches. it take me more then 5-10 min polishing the logo still there. i personally think the logo is printed very thick. even at the worlding also the same.
5) i personally think autosol work better then braso. so i decide to use autosol first. then continue to use braso as braso is more mild. provide even better finishing.
6) last but not least i also use the car wax another layer of protection and it further giving a better furnishing.
* Please only polish the casing when u using it for a long time and u no longer take it (too scratches)
* you do it at our own risk. i take mine and happy about it