Remove full name from login window In Mountain Lion, my full name is displayed at the bottom of the log in menu. As I want to sell my computer, I was wondering if there is a way to hide this? (it's the only place that you can see it as it is not the user name, and I can't change it in Sharing preferences).

I called Apple support, they told me there's a way to do it via Terminal, but they wanted to charge me for that. I looked up online, but I can't find a way to remove it.
Is this in the list of previously logged in users?

If you're selling your MacBook, you should consider re-installing the OS with a clean slate, rather than potentially leaving items behind.

You might find there's still a userid on the computer somewhere; you can remove it by running sudo dscl and then ls /Local/Default/Users to see if the username shows up there. delete /Local/Default/Users/name should get rid of it.