You're gonna have to sell it locally -- I think it's legal to ship if you label it
ORM-D but none of the common carriers will accept it. And it's illegal to ship without having it properly marked. So you might have better luck listing it in a local sale paper, like the Thrifty Nickel. I sold some ammo I didn't want that way a couple of years ago.
I'm pretty sure it's against Craigslist policy to sell ammo there, but you can check. If I'm wrong about the policy, that'll be your quickest way to sell it. Good luck.