To go out of morocco territory is like this: first you arrive in bir guendouz, the last police check point of morocco down south in western sahara. you have to leave your car closed and go stamp your passports on the first house on your left side. on the house of the left side is the first door on your left (which mights also changed for the left side).
then you have to go and make the duane of your veicule (if going out with private car of course)
the police will try to ask you for something. say no and they leave yo alone (this will not happen in the mauritanian side, police will only let you go after you give them same pens or pencils, t shirst, chocolate etc...)
Fondest memory: on the picture you have a dog that was on the house of the police checkpoint of mauritania 7km after bir guendouz.
it was normal to the police to ask people coming with their veicule for some money. i still got that when coming the first time, but when coming back again nobody asked, and then coming with my own car, nothing happend also.
usualy police officer would ask you for 100DH (10 euros) for the entrance of the car in the police complex before the costumes. you just have to have all your papers ok and you stamp the passport and go make the costume of your car and thats it, your off to go enter the landmine paradise.