Shoot it.
Really. Not going to be worth the gas money to get the stuff to the post office, as far as making your fortune goes.
If you go to any gun shows, stick the stuff in your pocket and cart it along. Chances are about fifty/fifty, that you can trade it straight across for modern ammo to one of the guys that collects the stuff.
Last batch of old ammo I took and traded off was a half brick of "Whiz-Bang" .22 shot shells I was given. The 'brick' box was in really nice minty shape, and the six boxes remaining inside were mint, never opened. I got 20 bucks, which I spent on ammo I could use. The guy got several nice boxes to sell, plus the nice brick box. He has to make something too.
Not exactly a lottery win, but it went where it was appreciated.
Cheers
Trev