third world clean

Like most kids, my son leaves at least a spoonfull of whatever he is eating randomly distributed around his plate. 3 peas in one corner, 2 in the other, 4 in the middle. Separately, not much. But generally at least a spoonfull if scraped all together. As we were making him scrape together that last spoonfull so he could go get a cookie for dessert, this was the conversation:

Son- "Is that good enough?"
Father- "Oh, come on. You can get one more scoop out of that."
Son (after much LOUD scraping)- "Now?"
Father- "Well, it's not third world clean, but it'll do..."

From the man who routinely leaves plates so clean you would almost not be able to tell he ate off of them, I am almost scared to ask just what his true definition of "third world clean" is...