The back cover of the iPhone 4 is glass, making it beautiful yet fragile. While there is extra shine there is also the possibility of breaking it. Because of this, we have noticed and increased number of people doing what they can to maintain the beauty aspect of the back glass. One such person recently asked about replacing his back glass, which we did.
What did he do to require new backglass? Well, he cleaned it. Yes, cleaning the back can ruin the back glass. This is a real bummer for anyone looking to maintain the aesthetics of their new phone. In Apples defense though, it may not have been the general process of cleaning the back glass that ruined. Rather, it is how he cleaned it; with a car buffer. A car buffer on the back of an iPhone 4 is an incredibly bad idea. It will scrape and scratch the glass. The damage was not enough for someone frugal to want to drop $90 on a replacement but it was noticeably damaged.
The saga does not end with a simple replacement though. When we gave him the new Apple factory black back glass he noticed a small discolored spot on the top right side and requested a new one, which we were happy to oblige. When looking at other Apple backcovers, we saw that a quarter of them has slight discoloration. One example was with a back cover that had a streak of discoloration across the bottom (the worst that we saw).
Personality types go a long way in noticing discolorations. This guy obviously was extremely concerned with having impeccable back glass, possibly in the same way the Howie Mandel washes his hands until they bleed.
It is still worth noting and posting about though. The back glass for all of it's beauty may come to you slightly corrupted. If this happens, let Apple know and maybe you will get somewhere. No matter what though, don't use a car buffer to clean it.