I did a little more investigating last night, but didn't come up with much... now I'm really regretting discarding the metal that was left behind in my oil pan (figured I had the pictures... why keep it).
So last night, I poured my waste oil back into the oil pan, let it settle, and then slowly poured from the surface back into the jugs. I noticed that collected on the surface of the oil was what appeared to be gold dust. Maybe this is normal, as I don't think I've ever looked at oil this closely before.
When I got to the bottom of the pan, I did find a few very small "chunks", but each time I tried to touch one, it would smash into more "gold dust" (might have just appeared gold due to the color of the oil?). I did attempt to run a magnet over some, but they wouldn't attract... still not convinced though, as the pieces were so small and could have been stuck to the oil... hence the reason I was trying to pick them up.
I didn't mention in the OP that I had also originally found some sort of white flake... maybe the size of a dime. I also found a much smaller white piece this time around. I'll post a picture below, as well as a picture of some of the waste oil on my finger so you can get an idea of color (looked pretty clean otherwise).
So, I'm going to have to find some time to jack the car up, re-drain the oil, and pull the filter. I didn't change the filter this time around since the filter only had about 1K miles on it... and I had already filled the car back up with new oil before I discovered the debris.
