The best all around way to clean this drive is with a program called Dban. It will be clean as a whistle if you run this program on the drive and would be safe to use in another computer when done IMHO:
Dban Complete Disk Eraser
Please note: Be sure you have all disks unhooked that you do not want formatted and cleaned, because this program while great has the capability to erase multiple disks at one time if hooked to the computer.