This is the problem I had been facing a few days back, when I had to uninstall super cache. Yesterday, I decided to give it another shot and reinstalled it. But the problem remains the same.
Here's the issue - the cache/expired files don't get deleted even after an hour. It's like I publish a post on the blog, and check it on other browsers and the post won't appear even if I clear the browser cache. I have to manually clear the cache in WP super cache settings and only then can I see the post on a different browser ( that is, the browser where I am not logged in to WP)
Can someone enlighten me on how this works and around when should the cache refresh automatically? The expired time set in my super cache is the default: 3600 seconds.