My best is a 1956 Philadelphia quarter. It was in really great shape, too, probably XF-40 or maybe even 45. I'd wager it sat in someone's change jar for decades.
I've been finding old nickels too. Got a 1941 the other day. Decent shape probs vf. I do better in random change than I ever did crhing
Last year I bought a sandwich at the local shop and got a 1946-P quarter in return change. It was worn, but it was still a good silver quarter. They are still out there, but getting rarer every day - since all of us are cherry picking them!
This has been a great year for me. Between the CoinStar reject slot and silver in change, I have gotten $1.35 FV.
I've trained my wife right. She was buying some second-hand stuff and handed the lady a couple of dimes. She immediately requested the coins back and gave her a quarter instead. She realized that the dime she gave her was probably silver. It turned out to be a 61 Roosevelt. I love that lady.
I picked up a pizza last week, and when I went to pay, I saw that there was a Presidential dollar and a half-dollar in the till. I asked to buy them. The half turned out to be a 1969-D.