Checking email leads

Hi, I have scraped nearly 500k of emails. I want to get them verified so I can sell them off.I have used AMS in the past to send my emails but not verify.I have thought about finding a freelancer but haven't looked into it yet.So any ideas on I how can verify all my emails so I know which are live and which are not?Thanks

Bump really need to know a way to check.

you can use atomic email verifier, its a bit slow but i believe it can handle it