This is on the web but when it comes to service calls such trickier is best not done. 1GB and smaller sticks are so cheap now that there's no reason to resort to tricks.

But just so you know how a web page on that.

http://www.trishtech.com/2011/06/restore-usb-flash-disk-back-to-full-capacity/

I will not write a tutorial on how to do this. If I did, you may get the idea that I support this. -> Get the right tool for the job. <-
Bob