[Jamesp]

If you are lucky, you can drop the oil pan and it will be accessible at that point. There is a screen on the intake, but I would not advise running the car with the foil in there. As you've already poured in oil to try and flush it out, it's either in your oil pan or in the structure / mechanicals above the oil pan and there's not much free room inside the motor above the oil pan. If it were me, I'd try the oil pan first because it's easy. If not there, I'd remove the filler tube from the top of the engine (harder) and see if it was there. You'll also be able to check the tube if it is out. Best of luck.