[Blind-sysadmins] removing a emulated cd rom drive from a usb stick

Hi all, We have a bunch of USB Sticks from a advertisement action we did last year. Those USB Sticks contain a cd drive which contains a pdf which is a few mb. I wonder if that drive can be removed? anyone knows special tools for that? linux or windows. Or are those often made with a second chip that emulates the cd drive with the pdf on? Greetings and thanks, Simon