Yes you can, to the best of my understanding. Although it seems to me that the best thing about the Juul tends to be the proprietary e-liquid, if you are looking for something that you can easily carry and still get a lot of satisfaction from a few puffs as an "on the go thing." I guess you could get nic salts to refill them, certainly, but I'm not sure I understand why a Juul purchase for on the go, as you can't refill the pods indefinitely I don't think, I'm wondering why not just a very small AIO tube mod or something, that's more adjustable?
Sorry, just to answer your question, yes you can. It's not the easiest thing ever but it's not stupendously hard, either.
Anna