Have you ever found anything interesting/dodgy/worrying from a previous owner in your car? Maybe it was an import and you found something from it's home country?
I once found something in the boot of the Beemer that can only be described as white powder. Possibly just some baby powder, possibly cocaine. I didn't find out exactly what it was!
in my gsi I found about £6 a nice Stanley multi bit screwdriver a handbag sized umbrella and some machined metal that turned out to be an important job that the previous owner thought he had lost (I did return it)
I did hear or read of someone finding steroids and a needle