Windshield - cleaning before installation

I'd like to prep my car before the windshield goes in. I have the old out and would like to clean up the tracks/frame area that the new rubber gasket/seal goes in. What do you all suggest to get all the old gunk and all out?

Also, any good or bad stories as to where I should buy the gasket/seal from? I've seen them on various places for $85 - $100 so far.

Thanks - George