@Vickie118 Airbnb now allows you to add a pet fee to the initial booking so that it's pre-paid along with the rental fees. But apparently they screwed it up by not allowing per-pet or per-night charges, so it only works as a sort of pre-emptive cleaning fee. Oh, and if the guest claims their pet is for "emotional support," you're not even allowed to charge that.
It's never an option to "charge" anything after checkout - all you can do at that point is send a Resolution Request, and if the guest declines to pay, Airbnb decides whether you get any compensation (meanwhile, you risk a retaliatory review). You might be able to recoup the cost of a professional deep cleaning, with receipts, but it's not guaranteed.