your answer was a bit to short for me. But you wrote it was just a quick look, so I guess you will come back. However, your short answer left me with the following questions:
Do you mean to remove the browser cache with Cookie.app? That option is already checked here. And also I already tried deleting the cache separately via the menu drop down. The bvg.de site still knows what I have searched before.
And what about Facebook? I am not able to invalidate a login session with Cookie.app. Can you test this?
Another Question: Is it possible to delete Safaris cookies from within a Safari Extension? The idea would be to delete Safaris cookies from within Safari, not just via NSHTTPCookieStorage, which does not delete cookies if Safari keeps running, at least in some cases (bvg.de/facebook).
If that is possible, one could create a Safari extension, that could communicate with Cookie.app and then do the delete job correctly. But I think I am two steps ahead. There are still some questions left open from my post before. Can you please reproduce all 3 of my tests bvg.de, sweetproductions.com and facebook.com?
What is a "cache cookie"? (I have not googled this so far.)
I repeated the test on sweetproductions.com. Right now I am logged in, but the cookie is not visible in Cookie.app. And also "delete unwanted" does not invalidate the login. I think to get this situation, one has to keep Safari running longer. Personally I keep Safari and my osx-session open for days or even weeks. I just close the lid of my mac-laptop when I stop working each day.
Restarting Cookie.app helped in that situation. After restart of Cookie.app the before empty cookie listing was full of cookies again, which then could be deleted. That invalidated the login on sweetproductions.com. I did not hinder bvg.de to remember my last search. Actually bvg.de is not listed in Cookie.app but in Safari->Settings->Privacy->cookielist I can see it.