I'm selling my laptop on ebay - how do I make sure all the personal information is cleared?

[aliceinlalaland]

As I speak people are bidding for my old iBook. Thing is, there are lots of websites that I regularly visit that 'guess' my username and password - is there a surefire way to clear all that? And also how do I make sure all the nooks and crannies of my mac are cleared of cookies etc (whatever the hell they are?!)

Thanks, all

Do you need to reformat the hardrive...?

Mac's offer the capability to "safely" erase everything on the hard disk drive. That means that it doesn't just go and throw away the index of what's on the disk but goes to every bit of the disk and blanks it. That doesn't make it absolutely impossible to get the data back but makes it very tricky indeed.

To do this to your laptops disk you'll need to boot off of the original CD, blank the hard disk and then at the end I'd reinstall the OS to get it back to how it was when you got your hands on it.

There are instructions for doing the secure erase here:
support.apple.com/kb/HT1820

Look for the section "Steps for zeroing data"

Badger that is incredibly helpful, thank you. Will look at that link shortly. Now just have to find the original disk - I have the OSX software disk but I'm not sure if that's the one I need.

"I have the OSX software disk but I'm not sure if that's the one I need."

That should be it, if it's the disk that came with your laptop then it's got OS X, the applications and some utilities all on there.