remove all of your files from the drive, then format the drive using the default file format. This will remove anything that shouldn't be there.
To prevent Windows from adding the Recycle Bin to your USB drive, insert the USB drive into your computer and right click the recycle bin on your desktop and choose properties. Follow the remaining steps below for your version of windows...
XP (all versions)
1. When the Recycle bin properties appears, on the Global tab, select the radio button to configure drives independently.
2. Click the tab that corresponds to your USB device.
3. Place a check in the box only for the USB drive that says "Do not move files to the recycle bin"
4. Click ok. If the recycle folder is still present, just ignore it. nothing will be placed into it from that point on.
Windows Vista/7
1. Click on your USB drive in the list of available drives.
2. Select the radio button that says "Do not move files to the recycle Bin"
3. Click ok. if the recycle folder is still present on your USB device, you can simply ignore it. nothing should be placed into it from this point on.