No tanks until at least next weekend. I've got some delrin to do, and help out some people who accidentally cracked the flanges on theirs.
PLEASE do not pry on the flanges that meet at the top/bottom of the tube. It's there strictly for aesthetics. The material these are made of is tough, but very brittle. The tops will come off I PROMISE!!! I just wiggle and pull or you can use Strprswpr's method. I never take the bottom cap off. I just wash it out during a carto change as one piece. It shouldn't be an issue now as I loosened everything up quite a bit. I had my 12 year old daughter check each and every one by taking the top cap off.
I have a little tip now. If you are having flooding problems go to a smaller hole in the carto. The new ones that just left have a single 1/32" hole in them. I've also found that if you move the hole up approx 1/4" above the top of the bottom cap it helps a lot too. Some of the cartos out there have a looser filler in them, and when you put the hole in the carto towards the bottom, gravity takes over and wins. With the hole slightly higher, it allows the filler to wick the juice better, and stop the leaking. You can't vape the tank dry, but you can use cartos that you haven't been able to use before. I had problems with the IKV Gold V2's, and now I'm on my 2nd day with absolutely NO leaking. I loved the cartos, but they were leaking like a sieve until I tried this. Great flavor and vapor with no leaking. I'm glad too, because I love Isaac's stuff.