Thank you Whiskey! I will check out that thread for more info. I did get it open, put a toothpick in the hole and kind of wiggled it, this let me get a fingernail under it and popped the cap off. It's kind of hard to explain and it was hard to see the cap.
BTW, started vaping about a year and a half ago, with no intention of quitting smoking. After a few weeks, I just stopped the analogs mostly because they are so messy and stinky, not to mention the prices going up all the time. My constant cough disappeared within 2 weeks and I realized that I hadn't had a true deep breath of air in years. It was amazing!