Hi,
Unfortunately, you can't most likely save all of them. However, if these were mine, I would take the dban program and wipe them clean, then format them and use them or try them.
http://dban.sourceforge.net/
Note: Be very careful that you have drives you don't want erased disconnected because you might make an error and erase something you want to keep. Just know that once you use this program on ANY drive, you will not be able to retreive that data. This is a high security erasing program that is free.