I remember, as a little kid, I was walking around one of my father's job sites with him and asked him, "what's this?" as I preceded to grab a hairy vine of poison ivy hanging off the side of a tree.

My father scooped me up, ran me over to his work truck, poured gasoline all over my hands, and then wiped them off with a rag.

Apparently it worked, because I never got poison ivy. I did get to learn what it is though.

(Another funny memory from that day is my father having to explain to my mother why I smelt like gasoline when she came to pick me up.)