['I let my cousin borrow my car for the weekend and when I got it back, it was filled with mcdonalds fries.', 'That is pretty gross! I hope he cleaned it up later.', 'He didnt. He said it wasnt his fault. I am beyond disgusted rigth now.']
That should be the last time you let him borrow it.
When my cousin returned my car to me, it was filled with garbage.