We are unable to delete cache. If we click the delete button in top toolbar OR go dashboard > wp super cache > contents tab > then click on Delete button .... and then view pages via different browsers or computers, the older cached pages are still served with older cache timestamps in the footer .... This is new as of our upgrade to 1.0 ... we've reinstalled to to no avail.
Just read this http://wordpress.org/support/topic/plugin-wp-super-cache-delete-cache-button-problem?replies=17 ... so not sure if it's same issue or not.
Also, we don't have "Delete Cache on all Blogs" button as indicated in that post ... and we are on multisite ...