I would do as mentioned above, and call the Sheriff, local police or troopers to take it from you. I was going to suggest going to a gun dealer, to have him take them off your hands for resale (you may or may not see any $$) but after reading what don wrote, I agree it is best to just turn them in.
If you have any guns that belonged to your dad, the police will take them as well. I found out something interesting after my husband died. I live in NY State, as you do, and with the SAFE act, I had 15 days from the day he died to dispose of his pistols, or risk a large fine. I did not know that, my brother found out. He hooked me up with a dealer who took them and they guy is trying to sell them for me. I also found that ignorance of the law is not an excuse, and I could have been fined even if I did not k now.
That does not apply to the ammo, though.