You might need to tweak the parameters in jon's example.
For example if your actor is 100 x 100 pixels it won't be fully off screen until its position has gone 50 pixels beyond the boundaries so you would need :
when self.position.x is < -50 when self.position.x is > 530 when self.position.y is < -50 when self.position.y is > 370
Comments
when self.position.x is < 0
when self.position.x is > 480
when self.position.y is < 0
when self.position.y is > 320
destroy actor
If the actor 's position moves offscreen it will get destroyed, this is for a landscape orientation.
For example if your actor is 100 x 100 pixels it won't be fully off screen until its position has gone 50 pixels beyond the boundaries so you would need :
when self.position.x is < -50
when self.position.x is > 530
when self.position.y is < -50
when self.position.y is > 370
Destroy if:
Self.Position.X < -(Self.Size.Width/2)
Self.Position.X > (Game.Display.Size.Width) + (Self.Size.Width/2)
Self.Position.Y < -(Self.Size.Height/2)
Self.Position.Y > (Game.Display.Size.Height) + (Self.Size.Height/2)