What are these marks on my PC? I used to have it setup on my floor for a while until I decided to clear some space and put it on my desk. Not exactly sure when they showed up, but it had to be while it was on the ground. I’ve never spilled anything on it nor have I tried to clean it with anything. Not really sure if it’s on the inside or outside as I’ve tried to wipe it off with a microfiber cloth on both. While I’m here, how do you guys clean the glass on your PC?