For years I've been frustrated by caulk and glue tubes that get thrown out half used because the end gets hard and there is no easy way to dig out the hardened caulk in the tip without destroying the tip or cutting a large hole that no longer will run a nice bead. So the other day I had a revelation. And I have now used my new technique 4 times - once for silicone caulk, once for painters caulk and twice for pl200. Get a drill and long drill bit and put it in the end of the tube and drill through the hardened end. The drill bit extracts the hard caulk, glue, etc, just the way it pulls out saw dust when you drill into wood. And Voila, no more wasted half used tubes of caulk. It's also a huge time saver, let me tell you. That's my tip for the day.