In front of God and everyone else he buried his finger to the first knuckle and probed the depths of his nostril, then removed it and studied the sample stuck between his fingernail and finger. Even from a distance I could tell he had "mined" quite a prize.
Then, to my astonishment, he stuck the green/yellow mess into his mouth and chewed it with a satisfied look on his face.
"You DIDN'T really do that in front of me, did you?"
Shocked out of his reverie as if he had forgotten anyone else could be watching he said, "What?"
"How could you do that? I didn't realize you were a Booger-eating moron!"
Sheephish look on his face...
"I like 'em. They're salty."
"Do you have any idea what you're eating when you eat those?"
No answer. He's smart enough to know he doesn't want to hear what I'm about to say...
"Let's say you go into a bathroom immediately after someone else has just had a HUGE bowel movement and the air still carries the remnants of that event. The reason you can smell what they have just done is because tiny bits of fecal matter are entering your nose and being filtered out. That stuff, and everything else you smell, ends up in the mucous in your nasal passages, which dries and becomes the stuff you so anxiously search for when you bury your finger in your nose. It's disgusting to think what else is in that 'salty' tidbit you're nibbling on."
"Yeah, I guess that's right".
And he turned and walked away.
I haven't seen him do it lately, but I think that's mostly because he's more careful about when and where he does his "treasure hunting".