Lol at some the comments. But yes as said before, heat gun or hair dryer. Start the edge of the vinyl and start peeling a little, then start applying the gun. You'll find the vinyl will become more pliable and the glue will soften, be careful not to heat it up too much either as it can melt the vinyl and if your really dumb with it ruin your paintwork, so use a sweeping action if the gun you have is really hot. And for goodness sakes keep the gun at a reasonable distance. Keep going till it's all off. You can use a blade to start the edges too, just gotta use some caution that's all. Otherwise if your too poonce, use your fingernail.
Turps or Prepsol or wax & grease remover is fine to remove the glue. All the sign shops use it so it's not bad for your paint. All it will do is just remove any wax on your paintwork as well.
For reference, when a car gets taken in to get vinyls put on, they prepsol/turps your car to remove the wax/polish to gain the best adhesion. And yes they use blades on your paintwork too. If your good enough it won't scratch it anyway.