If your in Vista, You defrag a second hard drive the same way you defrag your primary drive. Just tick all the hard drives you want to defrag from the check boxes.
In XP, Where you'd normally right click the C: drive, click properties then Tools, Then Defragment. Just do this on the second drive too..

To clean them, You have to be careful, It's always best to use software which has been programmed by experts to know which files are safe to remove and which aren't.

Programs like CCleaner are good.
You can also free up old restore points by right clicking a drive, clicking "Disk clean-up" then clicking "more" from the top, the bottom button is system restore, clicking that might make the window jam for a few seconds while it removes them, then returning to the normal tab, you can clear some other files too..

Try uninstalling old software you don't use any more too, You might have installed programs and forgotten about them, not using them for any purpose. Removing them can speed the system up too slightly by reducing the size of the registry and the master file table.

Hope that helps.  

The same way you access the first hard drives menu. Open my computer then right click the second drive. It's the same from there.

CCDisk? never heard of it. But usually software designed to clean-up the computer will be clearing out old system files, None of these exist on a second drive. To completely clear a second drive, just delete everything on it, or format it.

As long as it is the second drive and not drive C then formatting it won't cause any system problems.
If it was taken from another PC, then it's likely it was the C drive in that other PC, meaning it'll have all that old PC's system files on it, Your current PC isn't using them, it has it's own. so it's safe to format it. Making sure there's no music, pictures etc.. you want on it first...