Painting 69 Dart without removing the glass

Okay, another question. The Dart I am working on needs a full paint job. Problem is, the original windshield has a chip/crack in it, and I am not keen on removing/reinstalling it for fear of breaking it. That said, replacement glass is not terribly expensive (still a cost I would like to avoid), but it is not original. I have the trim off already. I think I can mask the seal off along with the glass. I wouldnt be able to cover the trim clips (which I also cannot remove because the glass is still in). This isnt a show car, but I do want it to look pretty darn good when done (may not be possible... after all, I am doing all the work). Anyone gone this route? Tips or advice on cleaning out as much of the channel as I can?

Separate but related. Both the windshield and back window (mostly back window) had a lot of crud under the trim that had collected in the channels around the seal. Like... nasty swamp debris looking stuff. Not the sealant, although that didnt help things. How do I go about preventing the build up of this rust promoting debris once I get to reassembly?

From what you mentioned the window is already broken.:D
( I have the same issue) a 4 inch crack on the passenger side after a rock on the hiway.
A friend gave me another windshield, but it's greenish colored so I'm not going to use it in my car.
I use a combo of water and compressed air to rinse and blow out the channels.