Invisible shield. Withstands anything...but whiteboard markers?

I have an Invisible Shield brand cover for my iPod. I've had one on my iPod Classic for like 2 years now. The thing seems indestructible.

It's been attacked by countless sharp and raspy objects (keys, coins, pocket knives), and it's always come out as clear as the day I bought it.

Until last night.

I went to the store with a bag in my pocket (there's a lot more to this story), the bag had Sharpie written on it. The sharpie transferred to my iPod.

Now, I wasn't overly concerned, because I figured I could scrape it off or, worst case scenario, find some chemical way to remove it. Scraping didn't really work (it's called "permanent marker" for a reason...it leaves permanent marks), so I turned to the internet for chemical solutions.

As it happens, dry-erase markers are supposed to be pretty good at removing permanent marker stains (on smooth surfaces). You just write over the marker, wait for it to dry, then erase it.

I couldn't find my markers at home, so I waited until I got to work. The sharpie came off fine, but the shield was left kind of foggy looking. I figured it might be marker residue, so I tried some whiteboard cleaner on it. It didn't help. I tried water, and water+soap.

Nothing.

I finally took a really close look at it, and the fogginess is caused by hundreds of small scratches. It's like the marker had a tiny cheese grater at the end of it.

Of all the things to kill my Invisible Shield, I wouldn't have suspected a whiteboard marker.

Fortunately, those shields come with a lifetime replacement guarantee, so I guess I'll be hitting the mall to find a kiosk.