Explain in your description how you will apply cleaning/person or per person charges of any type. As long as you dont have instant booking on, you can calculate the rate and send the enquirer the total amount via the "Send Special Offer" facility. A special offer doesnt just mean a discount!
I insist that a weekly cleaning fee applies for longer stays. So, if someone books 2 weeks, their Special Offer includes a second charge of cleaning fees. I do this for two reasons: 1) keep the standard of my place up by ensuring its cleaned at least once a week and 2) check on the place to ensure its not been misused.
For shorter stays, and for clean guests, I offer a refund outside the ABNB system. Not ideal (guests need to suppy a PayPal/bank account), but the only way I can see doing it.
AirBnB is just too inflexible!