Wiping bad disk (prior to replacement)

[RobertD]

G'Day
I have a Ready NAS Duo, (2 disk Raid array) after 4 months one of the Seagate 2Tb drives is returning constant SMART errors.
The shop has agreed to replace the hard drive. How do I wipe my data from one disk of the 2 disk raid array..??

If the disk was completely dead it would be no problem, but I do not want to hand over a disk with a copy of my data to the shop in usable condition..!!

Surely this isnt an unusual thing to come across, but I cant find any into to tell me how to do it.
Cheers
Rob

[evan2]

Do you have USB HDD dock? you may install HDD on Windows 7, the format it.

[RobertD]

No, unfortunately I am moving house (and my "stuff" is in storage) ...!!
Though I agree that would be an easy way out.....

Thanks for the suggestion.