So last night I grabbed my last carto from my 5 pack to try another flavor. When I popped off the filler cap, I saw that it appeared already filled with some type of brown liquid. Now, my previous cartos had what appeared to be brown liquid in the wick, but this one looked like it was full of the stuff when I looked around the sides of the cup. I had assumed this was the primer being talked about, but now after reading more recent posts I'm not so sure. Any idea what the heck this stuff was? It had a really strong smell, almost smelled like my RY4 liquid. I just rinsed it out real good before using it, but now I'm wondering if it's primer or something else. I don't think any of my cartos had a completely white wick even from the start.