I read some of these answers before, but not all. So here goes! Most seem to say that they wouldn't tell anyone, well I am quite sure that is impossible. You wouldn't tell your wife? BS!! She would tell her sister , and her sister would tell everyone!! Its impossible to keep a secrete like that. What would you do, just pay your morgage and car payments? Hahaha, Why even look for a treasure, if you are not going to use it? Most seem to fear the gov, but the the relatives will have a lot of good ideas on where to use the money.
I would spend it, and be happy while it lasted. Just spend it and be happy you found something. Going around from to coin dealer to dealer is not too smart, they are all connected, and know what is going on in the coin world. Soon your smart plan would crumble, and you might even have the police after you, thinking you stole the coins, or gold or whaterver. What do you do then? "No, I only dug it up!" back to square one!
If its a small find, just spend it!! If its a big find, then get a lawyer that can help you with this kind of problem. Does it cost money? sure it does, but so did your detector.
YOU cannot hide a million dollars!! Buy a nice car, with cash? Dont worry, the feds will be around to ask where you got the money. Car dealers have to report these kind of cash transactions, at least in some states.
Have fun with your million!!