It seems just gross to swallow the CO after sipping it through the teeth and swirled it all around for 20 minutes, lol, my natural instinct is to just get rid of it, I would truly gag if I tried to get it down. There's just no need for it? It's not that expensive. I don't drink from the bathtub water either after taking a bath, yuck, lol.
But, I don't believe it would be dangerous, not at all. Why? If there are any bad germs in the mix, they all die anyways in the stomach acid before they can do any harm.
I think the old Indians buried their oils as a ritual, "getting rid of the old spirits" or something like that. Maybe they believed it is harmful, but that doesn't mean it truly is.
I'm all for ingesting CO, but I want mine fresh, not sieved through my teeth for an extended period of time...*shiver* :)