Co-Founder & CTO of CareerGuide.com, I am a creative technologist & an entrepreneur working on the problems of education and career guidance, practicing lean start up in my day to day product life style. Would be good to call for: coding, tech questions, product feedback, ideation, brainstorming, entrepreneurship. Expertise: Product strategy and development, organic user growth, community development. I approach problems from technical and business angles, extensive knowledge around Internet application architecture, hiring, management, as well as product design methods.
There are few ways to do it:
1. 404 :- This will be too bad
2. 301: You can do this but as you have huge number of url, doing this will also not be a good approach
3.Canonical: This will be best way in your case, along with you should also do no-index and no-follow for all these pages