Don't spend $230 to get a replacement if you are going to sell it. Put it on Swappa a couple weeks before Sept announcement of iPhone 7 if you can. This is what I usually do, but I have a backup 3GS that I can BARELY manage to make it with.
Did a quick search on buffing out aluminum scratches and came up with this product:
http://www.amazon.com/Meguiars-G10307-ScratchX-2-0-oz/dp/B0002UNON8
Based on information in this older post - https://forums.macrumors.com/threads/remove-scratches-from-aluminium-unibody-macbook.657515/page-2
Best of luck.
Did a quick search on buffing out aluminum scratches and came up with this product:
http://www.amazon.com/Meguiars-G10307-ScratchX-2-0-oz/dp/B0002UNON8
Based on information in this older post - https://forums.macrumors.com/threads/remove-scratches-from-aluminium-unibody-macbook.657515/page-2
Best of luck.
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