I was cleaning the car, I do it from time to time, honestly. On the dashboard there is a covered tray for phone, keys etc. and in it there is a hole... a socket.
Get to the boot and open the bag of bits kindly left by Aggers, it was once his car y'know, and in there is a curly phone type lead with earphone jacks on each end. I always wondered what it was for.
It turns out that the socket in the dash tray turns the car CD player into an auxiliary player. I can plug the lead into a phone or mp3 player and play the tracks directly from them.
No more piles of CDs on the passenger seat.
Like most men I do no read instruction books or user guides, so this is the "find" of the century.