Ok, here is my story. I have my mini since February and it's been love at first sight. I've been having issues since the start with the o ring swelling. I use TV wintergreen exclusively. I started putting the o ring around the bottle neck and it works great except I get leakage. Now My mini only works sporadicly at best. I do have another that I bought off of another person and I tried my set up, attie, battery, drip tip on that last night and it works perfectly. So, now I know it's my green mini. The spring is getting rusted because of the constantly leaking. I tried using different o rings but the same thing always happens, it swells and comes out of the cap. Now I have to send my precious mini back and in the meantime, the purple one is going to get rusted as well. I need a different solution. I read that someone is using the dripper top by drilling a hole in it but I'm far from mechanically inclined. Please help!!!