When I was a child (yes, it was back in the middle of a previous century), our teachers warned us about drugs - and not to lick our fingers when leafing through a book.

They told us drug dealers spread drugs on the corners of book pages, then patrolled the sidewalks looking for people with the dazed stare of drug addicts to recruit new customers.

This is not something I just made up - this is something I experienced first hand.