I'm going to ask my friend to pay the $250 cleaning fee for the car I rented.
Why should he pay the fee?
Because he smoked in the car after I told him not to smoke and the rental company is charging me a cleaning fee.
It seems reasonable to ask your friend to pay for the car cleaning because they smoked in the car even though you asked him not to. Talk to him and help him to understand that paying the fee is his responsibility because of his smoking. I'm sure you can get him to agree to the payment.
I'm going to sue him instead.
He needs to pay for the smoke damage. Next time try to put your foot down and tell him no so you can prevent this kind of situation.