IF your digestive track is in good working condition, then it might be OK to swallow.
I'd hazard a guess that many people here at CZ have less than favorable flora in their stomachs, so we don't encourage swallowing spent oil.
The only doctor who studied this said not to swallow. The ayurvedics want you to go outside and spit it into a mud hole and bury it.
I just want to clarify that on this forum, we do not advocate swallowing at all.
But each person makes their own decision on this, and can do as they please. I'm not at all wishing to debate the issue, just the stance of this site since the inception. Larx, you are probably much healthier than many of us that had suffered from digestive problems throughout the years.
And by the way, after I found out seeds will not sprout in microwaved water, I stopped using my microwave, period. I think microwaves completely change the molecular structure of any substance put into it. They scare the living daylights out of me. It still freaks me out how much microwaved popcorn I ate throughout the years!!