Just how hard is it to dispose of unwanted hard drives? Pile them into a skip and take it to a metal recycling centre. That's not good enough if they have contained sensitive data. The data can be recovered. There have been plenty of tales about second-hand computers containing stored confidential information to make the point.

For example, here is a BBC story about the problem.

So thump the drives with a large hammer. What is the problem?

The problem is that it is environmentally friendlier to recycle hard drives but, and here is the second problem, you would rather their contents had been wiped clean.

Enter IBM with a service. Its Asset Recovery Solutions program will buy back certain PC gear and cleanse the hard drive and recycle it. A white paper is available from here that describes the service. It's been prepared by IBM Global Financing which suggests that there is significant money to be made here.

It's thought that some 150 million PCS will be sent for disposal next year (by a Carnegie Mellon study) so IBM could be right. If malicious people get hold of forensic software and hardware used by law enforcement agencies when inspecting PCs belonging to criminals, which are legitimately obtainable, then apparently deleted files can be recovered.

Computers at the end of their lease period are often returned to the lessor and may be written off. It's not just a case of getting rid of old, worn out PCs and simply re-formatting the hard drive to prevent data being recovered off it.

Even a reformatted hard drive could have data recovered from it as the majority of drive sectors are left untouched during re-formatting. The hard drives need to have a pattern of zeroes or ones written to every byte in every sector of the drive for the previously held data to be totally unrecoverable. Not written just once either; Techworld's David Cartwright wrote in a forum submission; "When I was with NSTL (test lab) I looked into this and it was generally accepted that a "proper delete" package that overwrites every sector seven times is sufficient to eradicate the data (the reason for multiple writes is that there's always some slack in the bearings and so the head may not quite hit the same spot for each sector each time)."

IBM's disk sanitising service will ensure that data can not be recovered from old drives. The white paper argues that companies could be at risk of financial penalties if they inadvertently divulge private information through disposing of old PCs or other computers. It makes sense, IBM claims, for a bona fide recycling and disk sanitisation service to be used and ensure that you avoid such risks. Use IBM as a third-party asset disposition vendor.

What about smaller companies who don't want to do this but still want to dispose of old PCs in an environmentally friendly way?

There are several decent waste disposal companies that will take on old PCs. Some are listed at this URL; www.telecomgreen.co.uk. For example, this for PCs and this for servers.

All responsible recyclers will make it clear that they cleanse or disable hard drives. If you are set on sending your old PCs to landfills via the general waste disposal service then extract the hard drives and apply a club hammer vigorously to render the mechanism inside useless. Otherwise contact IBM or one of the disposal organisations mentioned above.

By the way there is no truth in the rumour that IBM is adding its Asset Recovery Solutions program to its information lifecycle management offering, although logically ...