working with USB drive ( why does it remain full?)

Hopefully there is a simple answer to this and I am just doing it wrong. But when working with a USB drive, in this case a 2GB stick formatted to Fat32 through the disk utility option, after I've copied some files to it, e.g a few movies and eventualy deleted these. Although it shows as 2gb free again, I can't actualy copy anything to the drive as it shows as full.

Its like it is saving the information somewhere when I delete a file, but hidden. Im having to format the drive again in order to be able to use it.

Any suggestions ?

thanks in advance.

Have you emptied the trash with the drive connected?

I have not done, is this something I should be doing?

yes, if you're deleting them in finder it simple moves them to .Trashes until you empty the trash.