When asking permission I've often heard the landowner comment that if you find anything really valuable we'll have to split it. Sometimes they're joking but most of the time they mean it.
I try to put myself in their position and ask myself what I would do? Would I be OK with someone digging my property up and carting off something worth a lot of money? probably not.
So, I tell them before they ask that if I find anything of obvious high value or perhaps has family heirloom potential they'll be the first to know.
Last October after doing a lot of research I identified a property within 10 min of my house that had a number of 1800's home sites on it that are now long gone of course. I asked for and received permission under the conditions described above.
On my second trip to the site I found my first Gold coin in 20+ years of metal detecting, A Quarter Eagle which is now my Avatar on this site. The first person I called was my wife and the second was the landowner.
I met him at his house and showed him the Quarter Eagle. He was surprised and pleased at the same time. I reminded him of our agreement and asked what he would like to do? He told me well, you found it what would you want to do?
I said I would like to keep it and that I would have it appraised and pay him half of the appraised value of the coin. He said that would be fair so I now own the coin of course.
But what is the most valuable to me is that the Landowner owns 275 acres smack in the middle of an 1838 town that has come and gone. I now have unlimited access to the entire property any time I want to hunt, a gate key, and a little sign he gave me to hang on the gate when I'm there so that he knows I'm somewhere on 275 acres.
He told neighbors the story and 3 other Landowners have given me like permissions to their properties. I now have a little over 950 acres to hunt within 10 minutes of my house.
2 of the landowners are in their 80's and are walking history books, they know where all the old home sites were at and something about who lived there back then.
So, I fix myself a lunch a few days a week, load up and go enjoy the day. and yes I've found some very cool stuff.
I'm not saying this is the way everyone should go about it but it works for me.