I was hauling freight one night in a C402 when they guy with me said he just HAD to take a dump. So he unbuckled, picked up a cardboard box, went back and after a few seconds there was a horrifically disgusting smell in the cabin. Seriously, it was a paint peeler and I have NO IDEA how the smell made it forward given the age of the airframe and the amount of airflow through all the leaks in the cabin
I have to say I was tempted to haul back on the yoke, figuring that would make him weigh a little bit more than normal with the obvious consequences, but hey I'd probably have to fly with him again, so I held off on that one
When we landed he shoved the cardboard box, with the evidence into a regular bin on the edge of the apron near the terminal building. I'm not sure what else he could have done tbh, but still, what about the poor b@st@rd who had to empty the bin . . .