Recycle Bin on USB Stick?

I have an 8GB USB memory stick, and it appears to have space tied up in
deleted files that I can't find. Windows only shows about half the space
available, even though it doesn't display any files. I ran a drive storage
analysis app (disk pie) on it, and it shows a large amount of space
associated with "recycle" files. I assume this means there's a recycle bin
on the drive holding previously deleted files.

I tried to reformat the drive, but got some errors. Also made sure hidden
files were displayed, which they are (at least the setting is turned on to do
so).

Any tips on resolving this issue?

Thanks.