Any way to fix discoloration of a windshield?

I had taken a windshield out of a 64' Valiant for my 65' Dart. There is some brown discoloration along with remnats of the old seal inbetween the inside panel and outer of the windshield. Does anyone know of anything I can do to reverse this? or if I'd be better off getting a differant windshield. any help will be very honorable, thanks