Quoted from Daditude:WD-40 electrical contact cleaner. It is amazing for pinballs and other electronics. It is non-flammable, and dries almost instantly.
You can find it at Wal-Mart, Lowe's, Home Depot, etc.
It is a secret trick of some of the best pinball restorers/techs out there.
Is this a joke? Highly flammable and really has no place in pinball repair.