If you still have your collection of vinyl records, here’s something kinda cool.
You know that space near the centre of the record between where the songs end and the paper label starts? That’s called “dead wax,” an area of the disc that contains no sonic information. This space is left blank because when you get this close to the centre, the angle makes it very difficult for a tone arm to track the grooves.
Some artists didn’t like that space to go to waste. That’s why they began to inscribe bits of graffiti and secret messages into that area. The Clash like to do this. Just check out the inner grooves of albums like London Calling or Sandinista!
Joy Division used to do the same thing. And one of the ways to confirm that several Nirvana 7″ singles on Sub Pop are genuine is through the graffiti inscribe on the dead wax.