I look at like this, it's still the homeowner's property, until he sees it, are releases ownership to you. You approached him to hunt his property, what's in it for him? Share the experience, a silver dime melts for what, a dollar? You may not find much, or anything of value, no guaranties. If the homeowner want's some of the stuff or all, I'd be happy with photos. If you are finding good stuff, you might want to return, or he has neighbors, with property of similar age and history. It's in your best interest to leave the homeowner with a smile and good memories to share with his family and friends. Helps open more opportunities. Might suck sometimes, but if somebody is generous enough to let you dig up his yard, just for fun, he isn't likely to be that tight about wanting anything you find. We are all taught (conditioned) that anything on the ground, or dirty, is bad. Most people will look, but not want to touch. I don't clean anything much while out hunting anyway, just enough to identify what it might be, leave the details for later.
At the very least, you had fun, and will walk away with more than you started with. Most of the stuff we find is of little interest or value to most people. You can buy nice, clean shiny silver coins in many places, not to expensive either, it's just more fun for us finding them.