Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I won't go against this evidence, but all the dents, dinges and chips of my Al Mac have been done due to other factors. As per my hand usage, my Mac doesn't experience said effects.

I still hold to what I stated. 2 years after posting in this thread, all I have are dinges caused by bumps or minor falls.
 
It's an individual thing. Some people have lower ph which it seems can etch the aluminum. The same thing can happen when using harsh cleaners.

As silly as it sounds, a thin coat of carnauba wax can help protect the metal. I do this on bare metal machine surfaces where I can't use oil (woodworking) and it helps prevent rust. It certainly should not damage the aluminum as long as brands using harsh solvents are avoided.
 
I just wanted to point out that the finish on apples laptops is not paint, powder coat, or even bare aluminium. It is a layer of anodization, which is a layer of oxidation that is "grown" on the surface of the aluminium part.

This layer is harder than bare aluminium, reducing chances of scratching etc. It also makes the aluminium dyeable, as seen in some of apples other products such as iPhones and iPods.

Most users will do no harm to the anodization even after many years, but prolonged exposer to sweat can damage the coating over time.

Keeping it as dry as possible, and giving it a wipe down every so often will go a long way to keep it looking brand new for years.

My first gen unibody macbook's (late 2008) finish still looks like the day I bought it, ignoring imperfections causes by actual damage of course.

Hope this helps, cheers.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.