Dont use Acetone..NO WAY! It will destoy the case. Believe me. If put on thick, or left on for a few minutes it will melt the plastic. At the very least...it will severely fog the plastic. What I would recommend it to try a very mild abraisive. Like bob said, try toothpaste. If that doesnt work, then move up to standard type cleaning car wax like Turtle Wax. You may also want to try thinks like Goo B Gone, but try it on a small back portion first.

I have had EXCELLENT luck with the special high end car wax that I use for my car. Its what is recommended by BMW. No, I dont have a BMW, but my Uncle does. Once I tried it , i discovered it was the adsolute best wax in the entire civilized worlkd. It goes on really easy amd comes off really easy. And it leaves such an amazing deep shine. Best i have ever used. but heres the real cool thing. It takes fine scratches out of plastic too. and it brings back the luster too. The headlights and tail lights on my car has all kinds of scatches...but after the wax...they look like new. The name: Zymol. $12.95 and word every penny.

If those things dont work, move up to a mild polishing compound. Not rubbing compound, POLISHING compound.

But then again...the HHB is kinda cool.