Hi Heidi,
Payment in advance for postage is my new policy, after having to chase a guest who wanted the bag he left behind sent on to him in another country.....when the postage came to $50, he was slow to pay!
I now have outlined the procedure to be followed in my house rules: I will find out what the postage is, let them know and request payment through Airbnb, and when the funds are available, I'll post the item. Unfortunately, this means an extra trip to the post office and waiting in line if it's international (local I can do with the self service system). I have a lot of international guests (who seem to be among the most forgetful!) and the postage for some of those items is no joke! Some people may change their minds on getting their items back when they find out the cost - and gone are the days when I'll just automatically post the charger, phone cord, electrical adapter etc. with no extra cost.
Good luck with your hosting! Susie
Susie