There doesn't appear to be any corrosion at all on those rounds that is visible in the pic you provided. The "green" that's visible appears to be the SS109/M855 green tip coating that is flaking off (if that isn't SS109/M855 then I'd be a little worried about the corrosion if it won't clean off).
The nicks/dents/etc. don't appear to be anything out of the ordinary for loosely packed mil surplus stuff.
When you buy loosely packed surplus stuff...you shouldn't expect pristine ammo by any stretch of the imagination. It was surplused for a reason and the price is more or less likely to reflect that fact. If you want "pretty" ammo...then pay for it!
If you want ammo that sends lead downrange when you pull the trigger...well...there you go.