How do I delete a specific cookie by name in Safari?

I opted into an experimental new Stack feature (coming soonish!), and now I want to opt back out. To do so, all I have to do is delete a cookie called purple. It should be easy. Just go to Safari preferences, privacy, cookie details, and...

...hum.

I don't want to delete all of my Stack Exchange cookies, just the one I know the name of. Can I delete this cookie through Safari? If not, where do Safari's cookies live, so I can delete it by hand?

You can still see individual cookies using Safari in developer mode. Go to "Safari-->Preferences-->Advanced" and enable "Show Develop menu in menu bar". Navigate to the webpage that holds the cookie you are looking to remove. Go to Develop in the menu bar and "Show web inspector". On the left hand side there will be a folder "Cookies" that holds the data from that site. You can right click them and delete certain ones.