press ctl-d and it will hide detail brushes. to make brushes detail press ctl-m, to make them structural press ctl-shift-s (i think, look in the shortcut menu).
structual caulk doesn't show up as anything. its used when you want to build the map around vis.
hint brushes are used to create splits in the bsp tree. in this example http://www.shadowspawn.net/junk/hint.jpg whats on one side of the triangle won't see what's on the other side of the triangle.
